diff --git a/alethzero/Debugger.h b/alethzero/Debugger.h
index 76ef6a0d3..38ed973df 100644
--- a/alethzero/Debugger.h
+++ b/alethzero/Debugger.h
@@ -45,7 +45,7 @@ struct WorldState
 	dev::u256s stack;
 	dev::bytes memory;
 	dev::bigint gasCost;
-	std::map<dev::u256, dev::u256> storage;
+	std::unordered_map<dev::u256, dev::u256> storage;
 	std::vector<WorldState const*> levels;
 };
 
diff --git a/alethzero/ExportState.cpp b/alethzero/ExportState.cpp
index a8e47ad6a..c11132768 100644
--- a/alethzero/ExportState.cpp
+++ b/alethzero/ExportState.cpp
@@ -91,7 +91,7 @@ void ExportStateDialog::fillBlocks()
 	while (i > 0 && i >= m_recentBlocks)
 		ui->block->removeItem(i--);
 
-	h256Set blocks;
+	h256Hash blocks;
 	for (QString f: filters)
 	{
 		if (f.startsWith("#"))
@@ -153,13 +153,17 @@ void ExportStateDialog::generateJSON()
 		auto address = Address((byte const*)hba.data(), Address::ConstructFromPointer);
 		json << prefix << "\t\"" << toHex(address.ref()) << "\":\n\t{\n\t\t\"wei\": \"" << ethereum()->balanceAt(address, m_block) << "\",\n";
 		json << "\t\t\"code\": \"" << toHex(ethereum()->codeAt(address, m_block)) << "\",\n";
-		std::map<u256, u256> storage = ethereum()->storageAt(address, m_block);
+		std::unordered_map<u256, u256> storage = ethereum()->storageAt(address, m_block);
 		if (!storage.empty())
 		{
 			json << "\t\t\"storage\":\n\t\t{\n";
+			std::string storagePrefix;
 			for (auto s: storage)
-				json << "\t\t\t\"" << toHex(s.first) << "\": \"" << toHex(s.second) << "\"" << (s.first == storage.rbegin()->first ? "" : ",") <<"\n";
-			json << "\t\t}\n";
+			{
+				json << storagePrefix << "\t\t\t\"" << toHex(s.first) << "\": \"" << toHex(s.second) << "\"";
+				storagePrefix = ",\n";
+			}
+			json << "\n\t\t}\n";
 		}
 		json << "\t}";
 		prefix = ",\n";
diff --git a/alethzero/MainWin.cpp b/alethzero/MainWin.cpp
index e5504cab2..437e75576 100644
--- a/alethzero/MainWin.cpp
+++ b/alethzero/MainWin.cpp
@@ -1092,7 +1092,7 @@ void Main::refreshBlockChain()
 	auto const& bc = ethereum()->blockChain();
 	QStringList filters = ui->blockChainFilter->text().toLower().split(QRegExp("\\s+"), QString::SkipEmptyParts);
 
-	h256Set blocks;
+	h256Hash blocks;
 	for (QString f: filters)
 		if (f.size() == 64)
 		{
diff --git a/cmake/EthCompilerSettings.cmake b/cmake/EthCompilerSettings.cmake
index 9e9ae687e..0d6fd7907 100644
--- a/cmake/EthCompilerSettings.cmake
+++ b/cmake/EthCompilerSettings.cmake
@@ -55,6 +55,7 @@ endif ()
 
 if (PROFILING AND (("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")))
 	set(CMAKE_CXX_FLAGS "-g ${CMAKE_CXX_FLAGS}")
+	set(CMAKE_C_FLAGS "-g ${CMAKE_C_FLAGS}")
 	add_definitions(-DETH_PROFILING_GPERF)
 	set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -lprofiler")
 #	set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} -lprofiler")
diff --git a/libdevcore/Common.h b/libdevcore/Common.h
index e0872b5d4..36e57c44f 100644
--- a/libdevcore/Common.h
+++ b/libdevcore/Common.h
@@ -34,10 +34,13 @@
 #endif
 
 #include <map>
+#include <unordered_map>
 #include <vector>
 #include <set>
+#include <unordered_set>
 #include <functional>
 #include <boost/timer.hpp>
+#include <boost/functional/hash.hpp>
 #pragma warning(push)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-parameter"
@@ -84,6 +87,10 @@ using StringMap = std::map<std::string, std::string>;
 using u256Map = std::map<u256, u256>;
 using HexMap = std::map<bytes, std::string>;
 
+// Hash types.
+using StringHashMap = std::unordered_map<std::string, std::string>;
+using u256HashMap = std::unordered_map<u256, u256>;
+
 // String types.
 using strings = std::vector<std::string>;
 
@@ -215,4 +222,14 @@ inline dev::WithExisting max(dev::WithExisting _a, dev::WithExisting _b)
 	return static_cast<dev::WithExisting>(max(static_cast<int>(_a), static_cast<int>(_b)));
 }
 
+template <> struct hash<dev::u256>
+{
+	size_t operator()(dev::u256 const& _a) const
+	{
+		unsigned size = _a.backend().size();
+		auto limbs = _a.backend().limbs();
+		return boost::hash_range(limbs, limbs + size);
+	}
+};
+
 }
diff --git a/libdevcore/CommonData.h b/libdevcore/CommonData.h
index a0ea01a1b..6c1f34667 100644
--- a/libdevcore/CommonData.h
+++ b/libdevcore/CommonData.h
@@ -258,6 +258,14 @@ template <class T, class U> std::set<T>& operator+=(std::set<T>& _a, U const& _b
 	return _a;
 }
 
+/// Insert the contents of a container into an unordered_st
+template <class T, class U> std::unordered_set<T>& operator+=(std::unordered_set<T>& _a, U const& _b)
+{
+	for (auto const& i: _b)
+		_a.insert(i);
+	return _a;
+}
+
 /// Concatenate the contents of a container onto a vector
 template <class T, class U> std::vector<T>& operator+=(std::vector<T>& _a, U const& _b)
 {
diff --git a/libdevcore/FixedHash.h b/libdevcore/FixedHash.h
index 2cf81cb77..5ba96b9a8 100644
--- a/libdevcore/FixedHash.h
+++ b/libdevcore/FixedHash.h
@@ -147,17 +147,10 @@ public:
 	/// @returns a random valued object.
 	static FixedHash random() { return random(s_fixedHashEngine); }
 
-	/// A generic std::hash compatible function object.
 	struct hash
 	{
 		/// Make a hash of the object's data.
-		size_t operator()(FixedHash const& value) const
-		{
-			size_t h = 0;
-			for (auto i: value.m_data)
-				h = (h << (5 - h)) + i;
-			return h;
-		}
+		size_t operator()(FixedHash const& value) const;
 	};
 
 	template <unsigned P, unsigned M> inline FixedHash& shiftBloom(FixedHash<M> const& _h)
@@ -215,6 +208,23 @@ template<> inline bool FixedHash<32>::operator==(FixedHash<32> const& _other) co
 	return (hash1[0] == hash2[0]) && (hash1[1] == hash2[1]) && (hash1[2] == hash2[2]) && (hash1[3] == hash2[3]);
 }
 
+/// Fast std::hash compatible hash function object for h64.
+template<> inline size_t FixedHash<8>::hash::operator()(FixedHash<8> const& value) const
+{
+	const uint64_t*data = (const uint64_t*)value.data();
+	return (size_t)(*data);
+}
+
+/// Fast std::hash compatible hash function object for h160.
+template<> inline size_t FixedHash<20>::hash::operator()(FixedHash<20> const& value) const
+{
+	const uint64_t*data = (const uint64_t*)value.data();
+	uint64_t hash = data[0];
+	hash ^= data[1];
+	hash ^= ((const uint32_t*)value.data())[4];
+	return (size_t)hash;
+}
+
 /// Fast std::hash compatible hash function object for h256.
 template<> inline size_t FixedHash<32>::hash::operator()(FixedHash<32> const& value) const
 {
@@ -226,6 +236,21 @@ template<> inline size_t FixedHash<32>::hash::operator()(FixedHash<32> const& va
 	return (size_t)hash;
 }
 
+/// Fast std::hash compatible hash function object for h512.
+template<> inline size_t FixedHash<64>::hash::operator()(FixedHash<64> const& value) const
+{
+	const uint64_t*data = (const uint64_t*)value.data();
+	uint64_t hash = data[0];
+	hash ^= data[1];
+	hash ^= data[2];
+	hash ^= data[3];
+	hash ^= data[4];
+	hash ^= data[5];
+	hash ^= data[6];
+	hash ^= data[7];
+	return (size_t)hash;
+}
+
 /// Stream I/O for the FixedHash class.
 template <unsigned N>
 inline std::ostream& operator<<(std::ostream& _out, FixedHash<N> const& _h)
@@ -251,6 +276,8 @@ using h256s = std::vector<h256>;
 using h160s = std::vector<h160>;
 using h256Set = std::set<h256>;
 using h160Set = std::set<h160>;
+using h256Hash = std::unordered_set<h256>;
+using h160Hash = std::unordered_set<h160>;
 
 /// Convert the given value into h160 (160-bit unsigned integer) using the right 20 bytes.
 inline h160 right160(h256 const& _t)
@@ -282,6 +309,9 @@ inline std::string toString(h256s const& _bs)
 
 namespace std
 {
-	/// Forward std::hash<dev::h256> to dev::h256::hash.
+	/// Forward std::hash<dev::FixedHash> to dev::FixedHash::hash.
+	template<> struct hash<dev::h64>: dev::h64::hash {};
+	template<> struct hash<dev::h160>: dev::h160::hash {};
 	template<> struct hash<dev::h256>: dev::h256::hash {};
+	template<> struct hash<dev::h512>: dev::h512::hash {};
 }
diff --git a/libdevcore/Log.h b/libdevcore/Log.h
index f42e9cbdd..20ad9fd20 100644
--- a/libdevcore/Log.h
+++ b/libdevcore/Log.h
@@ -164,6 +164,30 @@ public:
 		}
 		m_sstr << EthLime "}" EthReset;
 	}
+	template <class T> void append(std::unordered_set<T> const& _t)
+	{
+		m_sstr << EthYellow "{" EthReset;
+		int n = 0;
+		for (auto const& i: _t)
+		{
+			m_sstr << (n++ ? EthYellow ", " EthReset : "");
+			append(i);
+		}
+		m_sstr << EthYellow "}" EthReset;
+	}
+	template <class T, class U> void append(std::unordered_map<T, U> const& _t)
+	{
+		m_sstr << EthLime "{" EthReset;
+		int n = 0;
+		for (auto const& i: _t)
+		{
+			m_sstr << (n++ ? EthLime ", " EthReset : "");
+			append(i.first);
+			m_sstr << (n++ ? EthLime ": " EthReset : "");
+			append(i.second);
+		}
+		m_sstr << EthLime "}" EthReset;
+	}
 	template <class T, class U> void append(std::pair<T, U> const& _t)
 	{
 		m_sstr << EthPurple "(" EthReset;
diff --git a/libdevcore/RLP.h b/libdevcore/RLP.h
index ac5e2ef1e..6e46807ab 100644
--- a/libdevcore/RLP.h
+++ b/libdevcore/RLP.h
@@ -362,6 +362,7 @@ public:
 	template <class _T> RLPStream& appendVector(std::vector<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
 	template <class _T, size_t S> RLPStream& append(std::array<_T, S> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
 	template <class _T> RLPStream& append(std::set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
+	template <class _T> RLPStream& append(std::unordered_set<_T> const& _s) { appendList(_s.size()); for (auto const& i: _s) append(i); return *this; }
 	template <class T, class U> RLPStream& append(std::pair<T, U> const& _s) { appendList(2); append(_s.first); append(_s.second); return *this; }
 
 	/// Appends a list.
diff --git a/libdevcrypto/Common.h b/libdevcrypto/Common.h
index 50072c1bf..b854e76a3 100644
--- a/libdevcrypto/Common.h
+++ b/libdevcrypto/Common.h
@@ -68,8 +68,8 @@ extern Address ZeroAddress;
 /// A vector of Ethereum addresses.
 using Addresses = h160s;
 
-/// A set of Ethereum addresses.
-using AddressSet = std::set<h160>;
+/// A hash table of Ethereum addresses.
+using AddressHash = std::unordered_set<h160>;
 
 /// A vector of secrets.
 using Secrets = h256s;
diff --git a/libdevcrypto/MemoryDB.cpp b/libdevcrypto/MemoryDB.cpp
index 907e6abe6..4b08db083 100644
--- a/libdevcrypto/MemoryDB.cpp
+++ b/libdevcrypto/MemoryDB.cpp
@@ -30,9 +30,9 @@ namespace dev
 const char* DBChannel::name() { return "TDB"; }
 const char* DBWarn::name() { return "TDB"; }
 
-std::map<h256, std::string> MemoryDB::get() const
+std::unordered_map<h256, std::string> MemoryDB::get() const
 {
-	std::map<h256, std::string> ret;
+	std::unordered_map<h256, std::string> ret;
 	for (auto const& i: m_main)
 		if (!m_enforceRefs || i.second.second > 0)
 			ret.insert(make_pair(i.first, i.second.first));
@@ -112,9 +112,9 @@ void MemoryDB::purge()
 			it = m_main.erase(it);
 }
 
-set<h256> MemoryDB::keys() const
+h256Hash MemoryDB::keys() const
 {
-	set<h256> ret;
+	h256Hash ret;
 	for (auto const& i: m_main)
 		if (i.second.second)
 			ret.insert(i.first);
diff --git a/libdevcrypto/MemoryDB.h b/libdevcrypto/MemoryDB.h
index 71428ecdb..3169d8fbc 100644
--- a/libdevcrypto/MemoryDB.h
+++ b/libdevcrypto/MemoryDB.h
@@ -21,7 +21,7 @@
 
 #pragma once
 
-#include <map>
+#include <unordered_map>
 #include <libdevcore/Common.h>
 #include <libdevcore/FixedHash.h>
 #include <libdevcore/Log.h>
@@ -45,7 +45,7 @@ public:
 	MemoryDB() {}
 
 	void clear() { m_main.clear(); }	// WARNING !!!! didn't originally clear m_refCount!!!
-	std::map<h256, std::string> get() const;
+	std::unordered_map<h256, std::string> get() const;
 
 	std::string lookup(h256 const& _h) const;
 	bool exists(h256 const& _h) const;
@@ -57,11 +57,11 @@ public:
 	void removeAux(h256 const& _h) { m_aux[_h].second = false; }
 	void insertAux(h256 const& _h, bytesConstRef _v) { m_aux[_h] = make_pair(_v.toBytes(), true); }
 
-	std::set<h256> keys() const;
+	h256Hash keys() const;
 
 protected:
-	std::map<h256, std::pair<std::string, unsigned>> m_main;
-	std::map<h256, std::pair<bytes, bool>> m_aux;
+	std::unordered_map<h256, std::pair<std::string, unsigned>> m_main;
+	std::unordered_map<h256, std::pair<bytes, bool>> m_aux;
 
 	mutable bool m_enforceRefs = false;
 };
diff --git a/libdevcrypto/TrieDB.h b/libdevcrypto/TrieDB.h
index ef628d20b..ff2bcc589 100644
--- a/libdevcrypto/TrieDB.h
+++ b/libdevcrypto/TrieDB.h
@@ -26,7 +26,6 @@
 #include <leveldb/db.h>
 #pragma warning(pop)
 
-#include <map>
 #include <memory>
 #include <libdevcore/Common.h>
 #include <libdevcore/Log.h>
@@ -105,7 +104,7 @@ public:
 
 	void debugPrint() {}
 
-	void descendKey(h256 _k, std::set<h256>& _keyMask, bool _wasExt, std::ostream* _out, int _indent = 0) const
+	void descendKey(h256 _k, h256Hash& _keyMask, bool _wasExt, std::ostream* _out, int _indent = 0) const
 	{
 		_keyMask.erase(_k);
 		if (_k == m_root && _k == c_shaNull)	// root allowed to be empty
@@ -113,7 +112,7 @@ public:
 		descendList(RLP(node(_k)), _keyMask, _wasExt, _out, _indent);	// if not, it must be a list
 	}
 
-	void descendEntry(RLP const& _r, std::set<h256>& _keyMask, bool _wasExt, std::ostream* _out, int _indent) const
+	void descendEntry(RLP const& _r, h256Hash& _keyMask, bool _wasExt, std::ostream* _out, int _indent) const
 	{
 		if (_r.isData() && _r.size() == 32)
 			descendKey(_r.toHash<h256>(), _keyMask, _wasExt, _out, _indent);
@@ -123,7 +122,7 @@ public:
 			BOOST_THROW_EXCEPTION(InvalidTrie());
 	}
 
-	void descendList(RLP const& _r, std::set<h256>& _keyMask, bool _wasExt, std::ostream* _out, int _indent) const
+	void descendList(RLP const& _r, h256Hash& _keyMask, bool _wasExt, std::ostream* _out, int _indent) const
 	{
 		if (_r.isList() && _r.itemCount() == 2 && (!_wasExt || _out))
 		{
@@ -144,9 +143,9 @@ public:
 			BOOST_THROW_EXCEPTION(InvalidTrie());
 	}
 
-	std::set<h256> leftOvers(std::ostream* _out = nullptr) const
+	h256Hash leftOvers(std::ostream* _out = nullptr) const
 	{
-		std::set<h256> k = m_db->keys();
+		h256Hash k = m_db->keys();
 		descendKey(m_root, k, false, _out);
 		return k;
 	}
@@ -431,7 +430,7 @@ public:
 	void insert(bytesConstRef _key, bytesConstRef _value) { Super::insert(_key, _value); m_secure.insert(_key, _value); syncRoot(); }
 	void remove(bytesConstRef _key) { Super::remove(_key); m_secure.remove(_key); syncRoot(); }
 
-	std::set<h256> leftOvers(std::ostream* = nullptr) const { return std::set<h256>{}; }
+	h256Hash leftOvers(std::ostream* = nullptr) const { return h256Hash{}; }
 	bool check(bool) const { return m_secure.check(false) && Super::check(false); }
 
 private:
diff --git a/libethcore/EthashAux.h b/libethcore/EthashAux.h
index 0389697f5..c90ee048e 100644
--- a/libethcore/EthashAux.h
+++ b/libethcore/EthashAux.h
@@ -75,12 +75,12 @@ private:
 	static EthashAux* s_this;
 	RecursiveMutex x_this;
 
-	std::map<h256, std::shared_ptr<LightAllocation>> m_lights;
-	std::map<h256, std::weak_ptr<FullAllocation>> m_fulls;
+	std::unordered_map<h256, std::shared_ptr<LightAllocation>> m_lights;
+	std::unordered_map<h256, std::weak_ptr<FullAllocation>> m_fulls;
 	FullType m_lastUsedFull;
 
 	Mutex x_epochs;
-	std::map<h256, unsigned> m_epochs;
+	std::unordered_map<h256, unsigned> m_epochs;
 	h256s m_seedHashes;
 };
 
diff --git a/libethereum/Account.h b/libethereum/Account.h
index 2cc962baa..660dc0a4c 100644
--- a/libethereum/Account.h
+++ b/libethereum/Account.h
@@ -134,8 +134,8 @@ public:
 	/// which encodes the base-state of the account's storage (upon which the storage is overlaid).
 	h256 baseRoot() const { assert(m_storageRoot); return m_storageRoot; }
 
-	/// @returns the storage overlay as a simple map.
-	std::map<u256, u256> const& storageOverlay() const { return m_storageOverlay; }
+	/// @returns the storage overlay as a simple hash map.
+	std::unordered_map<u256, u256> const& storageOverlay() const { return m_storageOverlay; }
 
 	/// Set a key/value pair in the account's storage. This actually goes into the overlay, for committing
 	/// to the trie later.
@@ -194,7 +194,7 @@ private:
 	h256 m_codeHash = EmptySHA3;
 
 	/// The map with is overlaid onto whatever storage is implied by the m_storageRoot in the trie.
-	std::map<u256, u256> m_storageOverlay;
+	std::unordered_map<u256, u256> m_storageOverlay;
 
 	/// The associated code for this account. The SHA3 of this should be equal to m_codeHash unless m_codeHash
 	/// equals c_contractConceptionCodeHash.
diff --git a/libethereum/AccountDiff.h b/libethereum/AccountDiff.h
index dd494c0a5..22107b958 100644
--- a/libethereum/AccountDiff.h
+++ b/libethereum/AccountDiff.h
@@ -62,7 +62,7 @@ struct AccountDiff
 	Diff<bool> exist;						///< The account's existance; was it created/deleted or not?
 	Diff<u256> balance;						///< The account's balance; did it alter?
 	Diff<u256> nonce;						///< The account's nonce; did it alter?
-	std::map<u256, Diff<u256>> storage;		///< The account's storage addresses; each has its own Diff.
+	std::unordered_map<u256, Diff<u256>> storage;		///< The account's storage addresses; each has its own Diff.
 	Diff<bytes> code;						///< The account's code; in general this should only have changed if exist also changed.
 };
 
diff --git a/libethereum/BlockChain.cpp b/libethereum/BlockChain.cpp
index 192cff34c..607fc586c 100644
--- a/libethereum/BlockChain.cpp
+++ b/libethereum/BlockChain.cpp
@@ -961,10 +961,10 @@ vector<unsigned> BlockChain::withBlockBloom(LogBloom const& _b, unsigned _earlie
 	return ret;
 }
 
-h256Set BlockChain::allUnclesFrom(h256 const& _parent) const
+h256Hash BlockChain::allUnclesFrom(h256 const& _parent) const
 {
 	// Get all uncles cited given a parent (i.e. featured as uncles/main in parent, parent + 1, ... parent + 5).
-	h256Set ret;
+	h256Hash ret;
 	h256 p = _parent;
 	for (unsigned i = 0; i < 6 && p != m_genesisHash; ++i, p = details(p).parent)
 	{
diff --git a/libethereum/BlockChain.h b/libethereum/BlockChain.h
index 12e1fc785..e77369534 100644
--- a/libethereum/BlockChain.h
+++ b/libethereum/BlockChain.h
@@ -72,7 +72,7 @@ struct BlockChainWarn: public LogChannel { static const char* name(); static con
 struct BlockChainDebug: public LogChannel { static const char* name(); static const int verbosity = 0; };
 
 // TODO: Move all this Genesis stuff into Genesis.h/.cpp
-std::map<Address, Account> const& genesisState();
+std::unordered_map<Address, Account> const& genesisState();
 
 ldb::Slice toSlice(h256 const& _h, unsigned _sub = 0);
 
@@ -206,7 +206,7 @@ public:
 	/// Get all blocks not allowed as uncles given a parent (i.e. featured as uncles/main in parent, parent + 1, ... parent + 5).
 	/// @returns set including the header-hash of every parent (including @a _parent) up to and including generation +5
 	/// togther with all their quoted uncles.
-	h256Set allUnclesFrom(h256 const& _parent) const;
+	h256Hash allUnclesFrom(h256 const& _parent) const;
 
 	/// Run through database and verify all blocks by reevaluating.
 	/// Will call _progress with the progress in this operation first param done, second total.
diff --git a/libethereum/BlockQueue.h b/libethereum/BlockQueue.h
index d9cb0ed53..a4e44b390 100644
--- a/libethereum/BlockQueue.h
+++ b/libethereum/BlockQueue.h
@@ -106,15 +106,15 @@ private:
 
 	bool invariants() const override;
 
-	mutable boost::shared_mutex m_lock;						///< General lock.
-	std::set<h256> m_drainingSet;							///< All blocks being imported.
-	std::set<h256> m_readySet;								///< All blocks ready for chain-import.
-	std::vector<std::pair<h256, bytes>> m_ready;			///< List of blocks, in correct order, ready for chain-import.
-	std::set<h256> m_unknownSet;							///< Set of all blocks whose parents are not ready/in-chain.
-	std::multimap<h256, std::pair<h256, bytes>> m_unknown;	///< For blocks that have an unknown parent; we map their parent hash to the block stuff, and insert once the block appears.
-	std::set<h256> m_knownBad;								///< Set of blocks that we know will never be valid.
-	std::multimap<unsigned, std::pair<h256, bytes>> m_future;///< Set of blocks that are not yet valid.
-	Signal m_onReady;										///< Called when a subsequent call to import blocks will return a non-empty container. Be nice and exit fast.
+	mutable boost::shared_mutex m_lock;									///< General lock.
+	h256Hash m_drainingSet;												///< All blocks being imported.
+	h256Hash m_readySet;												///< All blocks ready for chain-import.
+	std::vector<std::pair<h256, bytes>> m_ready;						///< List of blocks, in correct order, ready for chain-import.
+	h256Hash m_unknownSet;												///< Set of all blocks whose parents are not ready/in-chain.
+	std::unordered_multimap<h256, std::pair<h256, bytes>> m_unknown;	///< For blocks that have an unknown parent; we map their parent hash to the block stuff, and insert once the block appears.
+	h256Hash m_knownBad;												///< Set of blocks that we know will never be valid.
+	std::multimap<unsigned, std::pair<h256, bytes>> m_future;			///< Set of blocks that are not yet valid. Ordered by timestamp
+	Signal m_onReady;													///< Called when a subsequent call to import blocks will return a non-empty container. Be nice and exit fast.
 };
 
 }
diff --git a/libethereum/CachedAddressState.cpp b/libethereum/CachedAddressState.cpp
index e2fadc8b5..a25017793 100644
--- a/libethereum/CachedAddressState.cpp
+++ b/libethereum/CachedAddressState.cpp
@@ -51,9 +51,9 @@ bytes CachedAddressState::code() const
 	return h == EmptySHA3 ? bytes() : asBytes(m_o->lookup(h));
 }
 
-std::map<u256, u256> CachedAddressState::storage() const
+std::unordered_map<u256, u256> CachedAddressState::storage() const
 {
-	std::map<u256, u256> ret;
+	std::unordered_map<u256, u256> ret;
 	if (m_r)
 	{
 		SecureTrieDB<h256, OverlayDB> memdb(const_cast<OverlayDB*>(m_o), m_r[2].toHash<h256>());		// promise we won't alter the overlay! :)
diff --git a/libethereum/CachedAddressState.h b/libethereum/CachedAddressState.h
index 8a3c3a607..2a34c1b34 100644
--- a/libethereum/CachedAddressState.h
+++ b/libethereum/CachedAddressState.h
@@ -47,7 +47,7 @@ public:
 	bytes code() const;
 
 	// TODO: DEPRECATE.
-	std::map<u256, u256> storage() const;
+	std::unordered_map<u256, u256> storage() const;
 
 	AccountDiff diff(CachedAddressState const& _c);
 
diff --git a/libethereum/CanonBlockChain.cpp b/libethereum/CanonBlockChain.cpp
index 2cc1d24dc..f1de7292b 100644
--- a/libethereum/CanonBlockChain.cpp
+++ b/libethereum/CanonBlockChain.cpp
@@ -41,9 +41,9 @@ namespace js = json_spirit;
 
 #define ETH_CATCH 1
 
-std::map<Address, Account> const& dev::eth::genesisState()
+std::unordered_map<Address, Account> const& dev::eth::genesisState()
 {
-	static std::map<Address, Account> s_ret;
+	static std::unordered_map<Address, Account> s_ret;
 
 	if (s_ret.empty())
 	{
diff --git a/libethereum/CanonBlockChain.h b/libethereum/CanonBlockChain.h
index 619af87eb..df4ac2d88 100644
--- a/libethereum/CanonBlockChain.h
+++ b/libethereum/CanonBlockChain.h
@@ -45,7 +45,7 @@ namespace eth
 {
 
 // TODO: Move all this Genesis stuff into Genesis.h/.cpp
-std::map<Address, Account> const& genesisState();
+std::unordered_map<Address, Account> const& genesisState();
 
 /**
  * @brief Implements the blockchain database. All data this gives is disk-backed.
diff --git a/libethereum/Client.cpp b/libethereum/Client.cpp
index 01426527f..a43c98aa2 100644
--- a/libethereum/Client.cpp
+++ b/libethereum/Client.cpp
@@ -308,7 +308,7 @@ void Client::killChain()
 
 void Client::clearPending()
 {
-	h256Set changeds;
+	h256Hash changeds;
 	DEV_WRITE_GUARDED(x_postMine)
 	{
 		if (!m_postMine.pending().size())
@@ -345,7 +345,7 @@ static S& filtersStreamOut(S& _out, T const& _fs)
 	return _out;
 }
 
-void Client::appendFromNewPending(TransactionReceipt const& _receipt, h256Set& io_changed, h256 _transactionHash)
+void Client::appendFromNewPending(TransactionReceipt const& _receipt, h256Hash& io_changed, h256 _transactionHash)
 {
 	Guard l(x_filtersWatches);
 	for (pair<h256 const, InstalledFilter>& i: m_filters)
@@ -363,7 +363,7 @@ void Client::appendFromNewPending(TransactionReceipt const& _receipt, h256Set& i
 		}
 }
 
-void Client::appendFromNewBlock(h256 const& _block, h256Set& io_changed)
+void Client::appendFromNewBlock(h256 const& _block, h256Hash& io_changed)
 {
 	// TODO: more precise check on whether the txs match.
 	auto d = m_bc.info(_block);
@@ -496,7 +496,7 @@ void Client::syncTransactionQueue()
 	// returns TransactionReceipts, once for each transaction.
 	cwork << "postSTATE <== TQ";
 
-	h256Set changeds;
+	h256Hash changeds;
 	TransactionReceipts newPendingReceipts;
 
 	DEV_TIMED(working) DEV_WRITE_GUARDED(x_working)
@@ -552,7 +552,7 @@ void Client::onChainChanged(ImportRoute const& _ir)
 	if (auto h = m_host.lock())
 		h->noteNewBlocks();
 
-	h256Set changeds;
+	h256Hash changeds;
 	for (auto const& h: _ir.first)
 		appendFromNewBlock(h, changeds);
 	changeds.insert(ChainChangedFilter);
@@ -631,7 +631,7 @@ void Client::startMining()
 	onPostStateChanged();
 }
 
-void Client::noteChanged(h256Set const& _filters)
+void Client::noteChanged(h256Hash const& _filters)
 {
 	Guard l(x_filtersWatches);
 	if (_filters.size())
diff --git a/libethereum/Client.h b/libethereum/Client.h
index 946825828..e40356f86 100644
--- a/libethereum/Client.h
+++ b/libethereum/Client.h
@@ -228,15 +228,15 @@ protected:
 
 	/// Collate the changed filters for the bloom filter of the given pending transaction.
 	/// Insert any filters that are activated into @a o_changed.
-	void appendFromNewPending(TransactionReceipt const& _receipt, h256Set& io_changed, h256 _sha3);
+	void appendFromNewPending(TransactionReceipt const& _receipt, h256Hash& io_changed, h256 _sha3);
 
 	/// Collate the changed filters for the hash of the given block.
 	/// Insert any filters that are activated into @a o_changed.
-	void appendFromNewBlock(h256 const& _blockHash, h256Set& io_changed);
+	void appendFromNewBlock(h256 const& _blockHash, h256Hash& io_changed);
 
 	/// Record that the set of filters @a _filters have changed.
 	/// This doesn't actually make any callbacks, but incrememnts some counters in m_watches.
-	void noteChanged(h256Set const& _filters);
+	void noteChanged(h256Hash const& _filters);
 
 private:
 	/// Called when Worker is starting.
diff --git a/libethereum/ClientBase.cpp b/libethereum/ClientBase.cpp
index 136239cf3..8b3cd416f 100644
--- a/libethereum/ClientBase.cpp
+++ b/libethereum/ClientBase.cpp
@@ -147,7 +147,7 @@ h256 ClientBase::codeHashAt(Address _a, BlockNumber _block) const
 	return asOf(_block).codeHash(_a);
 }
 
-map<u256, u256> ClientBase::storageAt(Address _a, BlockNumber _block) const
+unordered_map<u256, u256> ClientBase::storageAt(Address _a, BlockNumber _block) const
 {
 	return asOf(_block).storage(_a);
 }
diff --git a/libethereum/ClientBase.h b/libethereum/ClientBase.h
index fc0b301ad..87888affe 100644
--- a/libethereum/ClientBase.h
+++ b/libethereum/ClientBase.h
@@ -100,7 +100,7 @@ public:
 	virtual u256 stateAt(Address _a, u256 _l, BlockNumber _block) const override;
 	virtual bytes codeAt(Address _a, BlockNumber _block) const override;
 	virtual h256 codeHashAt(Address _a, BlockNumber _block) const override;
-	virtual std::map<u256, u256> storageAt(Address _a, BlockNumber _block) const override;
+	virtual std::unordered_map<u256, u256> storageAt(Address _a, BlockNumber _block) const override;
 
 	virtual LocalisedLogEntries logs(unsigned _watchId) const override;
 	virtual LocalisedLogEntries logs(LogFilter const& _filter) const override;
@@ -172,9 +172,9 @@ protected:
 	TransactionQueue m_tq;							///< Maintains a list of incoming transactions not yet in a block on the blockchain.
 
 	// filters
-	mutable Mutex x_filtersWatches;					///< Our lock.
-	std::map<h256, InstalledFilter> m_filters;		///< The dictionary of filters that are active.
-	std::map<unsigned, ClientWatch> m_watches;		///< Each and every watch - these reference a filter.
+	mutable Mutex x_filtersWatches;							///< Our lock.
+	std::unordered_map<h256, InstalledFilter> m_filters;	///< The dictionary of filters that are active.
+	std::map<unsigned, ClientWatch> m_watches;				///< Each and every watch - these reference a filter.
 };
 
 }}
diff --git a/libethereum/DownloadMan.cpp b/libethereum/DownloadMan.cpp
index 1b73dca5b..05d0a533e 100644
--- a/libethereum/DownloadMan.cpp
+++ b/libethereum/DownloadMan.cpp
@@ -39,7 +39,7 @@ DownloadSub::~DownloadSub()
 	}
 }
 
-h256Set DownloadSub::nextFetch(unsigned _n)
+h256Hash DownloadSub::nextFetch(unsigned _n)
 {
 	Guard l(m_fetch);
 
@@ -51,7 +51,7 @@ h256Set DownloadSub::nextFetch(unsigned _n)
 	m_remaining.clear();
 
 	if (!m_man || m_man->chainEmpty())
-		return h256Set();
+		return h256Hash();
 
 	m_asked = (~(m_man->taken() + m_attempted)).lowest(_n);
 	if (m_asked.empty())
diff --git a/libethereum/DownloadMan.h b/libethereum/DownloadMan.h
index 82e0f09e2..2b41e660b 100644
--- a/libethereum/DownloadMan.h
+++ b/libethereum/DownloadMan.h
@@ -21,9 +21,9 @@
 
 #pragma once
 
-#include <map>
 #include <vector>
-#include <set>
+#include <unordered_set>
+#include <unordered_map>
 #include <libdevcore/Guards.h>
 #include <libdevcore/Worker.h>
 #include <libdevcore/RangeMask.h>
@@ -46,7 +46,7 @@ public:
 	~DownloadSub();
 
 	/// Finished last fetch - grab the next bunch of block hashes to download.
-	h256Set nextFetch(unsigned _n);
+	h256Hash nextFetch(unsigned _n);
 
 	/// Note that we've received a particular block. @returns true if we had asked for it but haven't received it yet.
 	bool noteBlock(h256 _hash);
@@ -71,8 +71,8 @@ private:
 	DownloadMan* m_man = nullptr;
 
 	mutable Mutex m_fetch;
-	h256Set m_remaining;
-	std::map<h256, unsigned> m_indices;
+	h256Hash m_remaining;
+	std::unordered_map<h256, unsigned> m_indices;
 	RangeMask<unsigned> m_asked;
 	RangeMask<unsigned> m_attempted;
 };
@@ -155,7 +155,7 @@ private:
 	RangeMask<unsigned> m_blocksGot;
 
 	mutable SharedMutex x_subs;
-	std::set<DownloadSub*> m_subs;
+	std::unordered_set<DownloadSub*> m_subs;
 };
 
 }
diff --git a/libethereum/EthereumHost.cpp b/libethereum/EthereumHost.cpp
index 299984a16..72ee1854d 100644
--- a/libethereum/EthereumHost.cpp
+++ b/libethereum/EthereumHost.cpp
@@ -21,7 +21,6 @@
 
 #include "EthereumHost.h"
 
-#include <set>
 #include <chrono>
 #include <thread>
 #include <libdevcore/Common.h>
@@ -184,7 +183,7 @@ void EthereumHost::doWork()
 void EthereumHost::maintainTransactions()
 {
 	// Send any new transactions.
-	map<std::shared_ptr<EthereumPeer>, h256s> peerTransactions;
+	unordered_map<std::shared_ptr<EthereumPeer>, h256s> peerTransactions;
 	auto ts = m_tq.transactions();
 	for (auto const& i: ts)
 	{
diff --git a/libethereum/EthereumHost.h b/libethereum/EthereumHost.h
index baa850b5c..d53c3cc79 100644
--- a/libethereum/EthereumHost.h
+++ b/libethereum/EthereumHost.h
@@ -22,9 +22,9 @@
 #pragma once
 
 #include <mutex>
-#include <map>
+#include <unordered_map>
 #include <vector>
-#include <set>
+#include <unordered_set>
 #include <memory>
 #include <utility>
 #include <thread>
@@ -97,7 +97,7 @@ private:
 	/// Get a bunch of needed blocks.
 	/// Removes them from our list of needed blocks.
 	/// @returns empty if there's no more blocks left to fetch, otherwise the blocks to fetch.
-	h256Set neededBlocks(h256Set const& _exclude);
+	h256Hash neededBlocks(h256Hash const& _exclude);
 
 	///	Check to see if the network peer-state initialisation has happened.
 	bool isInitialised() const { return (bool)m_latestBlockSent; }
@@ -121,9 +121,9 @@ private:
 	DownloadMan m_man;
 
 	h256 m_latestBlockSent;
-	h256Set m_transactionsSent;
+	h256Hash m_transactionsSent;
 
-	std::set<p2p::NodeId> m_banned;
+	std::unordered_set<p2p::NodeId> m_banned;
 
 	bool m_newTransactions = false;
 	bool m_newBlocks = false;
diff --git a/libethereum/EthereumPeer.h b/libethereum/EthereumPeer.h
index 75ebab02f..54f7ad829 100644
--- a/libethereum/EthereumPeer.h
+++ b/libethereum/EthereumPeer.h
@@ -23,7 +23,6 @@
 
 #include <mutex>
 #include <array>
-#include <set>
 #include <memory>
 #include <utility>
 
@@ -140,9 +139,9 @@ private:
 	bool m_requireTransactions = false;
 
 	Mutex x_knownBlocks;
-	h256Set m_knownBlocks;					///< Blocks that the peer already knows about (that don't need to be sent to them).
+	h256Hash m_knownBlocks;					///< Blocks that the peer already knows about (that don't need to be sent to them).
 	Mutex x_knownTransactions;
-	h256Set m_knownTransactions;			///< Transactions that the peer already knows of.
+	h256Hash m_knownTransactions;			///< Transactions that the peer already knows of.
 
 };
 
diff --git a/libethereum/ExtVM.h b/libethereum/ExtVM.h
index 8807bcd58..1a2d180dd 100644
--- a/libethereum/ExtVM.h
+++ b/libethereum/ExtVM.h
@@ -91,8 +91,8 @@ public:
 	State& state() const { return m_s; }
 
 private:
-	State& m_s;										///< A reference to the base state.
-	std::map<Address, Account> m_origCache;			///< The cache of the address states (i.e. the externalities) as-was prior to the execution.
+	State& m_s;											///< A reference to the base state.
+	std::unordered_map<Address, Account> m_origCache;	///< The cache of the address states (i.e. the externalities) as-was prior to the execution.
 };
 
 }
diff --git a/libethereum/Interface.h b/libethereum/Interface.h
index ba68e976e..f36d0f2c1 100644
--- a/libethereum/Interface.h
+++ b/libethereum/Interface.h
@@ -100,14 +100,14 @@ public:
 	u256 stateAt(Address _a, u256 _l) const { return stateAt(_a, _l, m_default); }
 	bytes codeAt(Address _a) const { return codeAt(_a, m_default); }
 	h256 codeHashAt(Address _a) const { return codeHashAt(_a, m_default); }
-	std::map<u256, u256> storageAt(Address _a) const { return storageAt(_a, m_default); }
+	std::unordered_map<u256, u256> storageAt(Address _a) const { return storageAt(_a, m_default); }
 
 	virtual u256 balanceAt(Address _a, BlockNumber _block) const = 0;
 	virtual u256 countAt(Address _a, BlockNumber _block) const = 0;
 	virtual u256 stateAt(Address _a, u256 _l, BlockNumber _block) const = 0;
 	virtual bytes codeAt(Address _a, BlockNumber _block) const = 0;
 	virtual h256 codeHashAt(Address _a, BlockNumber _block) const = 0;
-	virtual std::map<u256, u256> storageAt(Address _a, BlockNumber _block) const = 0;
+	virtual std::unordered_map<u256, u256> storageAt(Address _a, BlockNumber _block) const = 0;
 
 	// [LOGS API]
 	
diff --git a/libethereum/LogFilter.h b/libethereum/LogFilter.h
index 304fab317..97ff5a3b1 100644
--- a/libethereum/LogFilter.h
+++ b/libethereum/LogFilter.h
@@ -67,8 +67,8 @@ public:
 	friend std::ostream& dev::eth::operator<<(std::ostream& _out, dev::eth::LogFilter const& _s);
 
 private:
-	AddressSet m_addresses;
-	std::array<h256Set, 4> m_topics;
+	AddressHash m_addresses;
+	std::array<h256Hash, 4> m_topics;
 	unsigned m_earliest = 0;
 	unsigned m_latest = LatestBlock;
 };
diff --git a/libethereum/Precompiled.cpp b/libethereum/Precompiled.cpp
index 0fd5cb45b..cdcb4a46a 100644
--- a/libethereum/Precompiled.cpp
+++ b/libethereum/Precompiled.cpp
@@ -81,7 +81,7 @@ static bytes identityCode(bytesConstRef _in)
 	return _in.toBytes();
 }
 
-static const std::map<unsigned, PrecompiledAddress> c_precompiled =
+static const std::unordered_map<unsigned, PrecompiledAddress> c_precompiled =
 {
 	{ 1, { [](bytesConstRef) -> bigint { return c_ecrecoverGas; }, ecrecoverCode }},
 	{ 2, { [](bytesConstRef i) -> bigint { return c_sha256Gas + (i.size() + 31) / 32 * c_sha256WordGas; }, sha256Code }},
@@ -89,7 +89,7 @@ static const std::map<unsigned, PrecompiledAddress> c_precompiled =
 	{ 4, { [](bytesConstRef i) -> bigint { return c_identityGas + (i.size() + 31) / 32 * c_identityWordGas; }, identityCode }}
 };
 
-std::map<unsigned, PrecompiledAddress> const& dev::eth::precompiled()
+std::unordered_map<unsigned, PrecompiledAddress> const& dev::eth::precompiled()
 {
 	return c_precompiled;
 }
diff --git a/libethereum/Precompiled.h b/libethereum/Precompiled.h
index c65cd9a63..bded27386 100644
--- a/libethereum/Precompiled.h
+++ b/libethereum/Precompiled.h
@@ -21,7 +21,7 @@
 
 #pragma once
 
-#include <map>
+#include <unordered_map>
 #include <functional>
 #include <libdevcore/CommonData.h>
 
@@ -38,7 +38,7 @@ struct PrecompiledAddress
 };
 
 /// Info on precompiled contract accounts baked into the protocol.
-std::map<unsigned, PrecompiledAddress> const& precompiled();
+std::unordered_map<unsigned, PrecompiledAddress> const& precompiled();
 
 }
 }
diff --git a/libethereum/State.cpp b/libethereum/State.cpp
index 83a78e1e8..9156820b9 100644
--- a/libethereum/State.cpp
+++ b/libethereum/State.cpp
@@ -208,9 +208,9 @@ StateDiff State::diff(State const& _c) const
 {
 	StateDiff ret;
 
-	std::set<Address> ads;
-	std::set<Address> trieAds;
-	std::set<Address> trieAdsD;
+	std::unordered_set<Address> ads;
+	std::unordered_set<Address> trieAds;
+	std::unordered_set<Address> trieAdsD;
 
 	auto trie = SecureTrieDB<Address, OverlayDB>(const_cast<OverlayDB*>(&m_db), rootHash());
 	auto trieD = SecureTrieDB<Address, OverlayDB>(const_cast<OverlayDB*>(&_c.m_db), _c.rootHash());
@@ -246,7 +246,7 @@ void State::ensureCached(Address _a, bool _requireCode, bool _forceCreate) const
 	ensureCached(m_cache, _a, _requireCode, _forceCreate);
 }
 
-void State::ensureCached(std::map<Address, Account>& _cache, Address _a, bool _requireCode, bool _forceCreate) const
+void State::ensureCached(std::unordered_map<Address, Account>& _cache, Address _a, bool _requireCode, bool _forceCreate) const
 {
 	auto it = _cache.find(_a);
 	if (it == _cache.end())
@@ -426,10 +426,10 @@ u256 State::enactOn(bytesConstRef _block, BlockInfo const& _bi, BlockChain const
 	return ret;
 }
 
-map<Address, u256> State::addresses() const
+unordered_map<Address, u256> State::addresses() const
 {
 #if ETH_FATDB
-	map<Address, u256> ret;
+	unordered_map<Address, u256> ret;
 	for (auto i: m_cache)
 		if (i.second.isAlive())
 			ret[i.first] = i.second.balance();
@@ -649,9 +649,9 @@ u256 State::enact(bytesConstRef _block, BlockChain const& _bc, ImportRequirement
 	if (rlp[2].itemCount() > 2)
 		BOOST_THROW_EXCEPTION(TooManyUncles());
 
-	set<Nonce> nonces = { m_currentBlock.nonce };
+	unordered_set<Nonce> nonces = { m_currentBlock.nonce };
 	vector<BlockInfo> rewarded;
-	set<h256> knownUncles = _bc.allUnclesFrom(m_currentBlock.parentHash);
+	h256Hash knownUncles = _bc.allUnclesFrom(m_currentBlock.parentHash);
 
 	for (auto const& i: rlp[2])
 	{
@@ -805,7 +805,7 @@ void State::commitToMine(BlockChain const& _bc)
 	{
 		// Find great-uncles (or second-cousins or whatever they are) - children of great-grandparents, great-great-grandparents... that were not already uncles in previous generations.
 //		cout << "Checking " << m_previousBlock.hash << ", parent=" << m_previousBlock.parentHash << endl;
-		set<h256> knownUncles = _bc.allUnclesFrom(m_currentBlock.parentHash);
+		h256Hash knownUncles = _bc.allUnclesFrom(m_currentBlock.parentHash);
 		auto p = m_previousBlock.parentHash;
 		for (unsigned gen = 0; gen < 6 && p != _bc.genesisHash() && unclesCount < 2; ++gen, p = _bc.details(p).parent)
 		{
@@ -1016,9 +1016,9 @@ u256 State::storage(Address _id, u256 _memory) const
 	return ret;
 }
 
-map<u256, u256> State::storage(Address _id) const
+unordered_map<u256, u256> State::storage(Address _id) const
 {
-	map<u256, u256> ret;
+	unordered_map<u256, u256> ret;
 
 	ensureCached(_id, false, false);
 	auto it = m_cache.find(_id);
diff --git a/libethereum/State.h b/libethereum/State.h
index e3468c24c..74d75685c 100644
--- a/libethereum/State.h
+++ b/libethereum/State.h
@@ -22,7 +22,6 @@
 #pragma once
 
 #include <array>
-#include <map>
 #include <unordered_map>
 #include <libdevcore/Common.h>
 #include <libdevcore/RLP.h>
@@ -142,7 +141,7 @@ public:
 
 	/// @returns the set containing all addresses currently in use in Ethereum.
 	/// @throws InterfaceNotSupported if compiled without ETH_FATDB.
-	std::map<Address, u256> addresses() const;
+	std::unordered_map<Address, u256> addresses() const;
 
 	/// Get the header information on the present block.
 	BlockInfo const& info() const { return m_currentBlock; }
@@ -238,8 +237,8 @@ public:
 
 	/// Get the storage of an account.
 	/// @note This is expensive. Don't use it unless you need to.
-	/// @returns std::map<u256, u256> if no account exists at that address.
-	std::map<u256, u256> storage(Address _contract) const;
+	/// @returns std::unordered_map<u256, u256> if no account exists at that address.
+	std::unordered_map<u256, u256> storage(Address _contract) const;
 
 	/// Get the code of an account.
 	/// @returns bytes() if no account exists at that address.
@@ -263,7 +262,7 @@ public:
 	Transactions const& pending() const { return m_transactions; }
 
 	/// Get the list of hashes of pending transactions.
-	h256Set const& pendingHashes() const { return m_transactionSet; }
+	h256Hash const& pendingHashes() const { return m_transactionSet; }
 
 	/// Get the transaction receipt for the transaction of the given index.
 	TransactionReceipt const& receipt(unsigned _i) const { return m_receipts[_i]; }
@@ -334,7 +333,7 @@ private:
 	void ensureCached(Address _a, bool _requireCode, bool _forceCreate) const;
 
 	/// Retrieve all information about a given address into a cache.
-	void ensureCached(std::map<Address, Account>& _cache, Address _a, bool _requireCode, bool _forceCreate) const;
+	void ensureCached(std::unordered_map<Address, Account>& _cache, Address _a, bool _requireCode, bool _forceCreate) const;
 
 	/// Execute the given block, assuming it corresponds to m_currentBlock.
 	/// Throws on failure.
@@ -355,10 +354,10 @@ private:
 	SecureTrieDB<Address, OverlayDB> m_state;	///< Our state tree, as an OverlayDB DB.
 	Transactions m_transactions;				///< The current list of transactions that we've included in the state.
 	TransactionReceipts m_receipts;				///< The corresponding list of transaction receipts.
-	std::set<h256> m_transactionSet;			///< The set of transaction hashes that we've included in the state.
+	h256Hash m_transactionSet;					///< The set of transaction hashes that we've included in the state.
 	OverlayDB m_lastTx;
 
-	mutable std::map<Address, Account> m_cache;	///< Our address cache. This stores the states of each address that has (or at least might have) been changed.
+	mutable std::unordered_map<Address, Account> m_cache;	///< Our address cache. This stores the states of each address that has (or at least might have) been changed.
 
 	BlockInfo m_previousBlock;					///< The previous block's information.
 	BlockInfo m_currentBlock;					///< The current block's information.
@@ -380,7 +379,7 @@ private:
 std::ostream& operator<<(std::ostream& _out, State const& _s);
 
 template <class DB>
-void commit(std::map<Address, Account> const& _cache, DB& _db, SecureTrieDB<Address, DB>& _state)
+void commit(std::unordered_map<Address, Account> const& _cache, DB& _db, SecureTrieDB<Address, DB>& _state)
 {
 	for (auto const& i: _cache)
 		if (i.second.isDirty())
diff --git a/libethereum/TransactionQueue.h b/libethereum/TransactionQueue.h
index 69e1c935f..50fcea574 100644
--- a/libethereum/TransactionQueue.h
+++ b/libethereum/TransactionQueue.h
@@ -55,7 +55,7 @@ public:
 
 	void drop(h256 const& _txHash);
 
-	std::map<h256, Transaction> transactions() const { ReadGuard l(m_lock); return m_current; }
+	std::unordered_map<h256, Transaction> transactions() const { ReadGuard l(m_lock); return m_current; }
 	std::pair<unsigned, unsigned> items() const { ReadGuard l(m_lock); return std::make_pair(m_current.size(), m_unknown.size()); }
 	u256 maxNonce(Address const& _a) const;
 
@@ -72,14 +72,14 @@ private:
 	void insertCurrent_WITH_LOCK(std::pair<h256, Transaction> const& _p);
 	bool removeCurrent_WITH_LOCK(h256 const& _txHash);
 
-	mutable SharedMutex m_lock;										///< General lock.
-	std::set<h256> m_known;											///< Hashes of transactions in both sets.
-	std::map<h256, Transaction> m_current;							///< Map of SHA3(tx) to tx.
-	std::multimap<Address, std::pair<h256, Transaction>> m_unknown;	///< For transactions that have a future nonce; we map their sender address to the tx stuff, and insert once the sender has a valid TX.
-	std::map<h256, std::function<void(ImportResult)>> m_callbacks;	///< Called once.
-	std::set<h256> m_dropped;										///< Transactions that have previously been dropped.
-	std::multimap<Address, h256> m_senders;							///< Mapping from the sender address to the transaction hash; useful for determining the nonce of a given sender.
-	Signal m_onReady;												///< Called when a subsequent call to import transactions will return a non-empty container. Be nice and exit fast.
+	mutable SharedMutex m_lock;													///< General lock.
+	h256Hash m_known;															///< Hashes of transactions in both sets.
+	std::unordered_map<h256, Transaction> m_current;							///< Map of SHA3(tx) to tx.
+	std::unordered_multimap<Address, std::pair<h256, Transaction>> m_unknown;	///< For transactions that have a future nonce; we map their sender address to the tx stuff, and insert once the sender has a valid TX.
+	std::unordered_map<h256, std::function<void(ImportResult)>> m_callbacks;	///< Called once.
+	h256Hash m_dropped;															///< Transactions that have previously been dropped.
+	std::multimap<Address, h256> m_senders;										///< Mapping from the sender address to the transaction hash; useful for determining the nonce of a given sender.
+	Signal m_onReady;															///< Called when a subsequent call to import transactions will return a non-empty container. Be nice and exit fast.
 };
 
 }
diff --git a/libethereum/TransactionReceipt.h b/libethereum/TransactionReceipt.h
index 1e0663054..0a0b154f4 100644
--- a/libethereum/TransactionReceipt.h
+++ b/libethereum/TransactionReceipt.h
@@ -22,7 +22,6 @@
 #pragma once
 
 #include <array>
-#include <map>
 #include <libdevcore/Common.h>
 #include <libdevcore/RLP.h>
 #include <libevm/ExtVMFace.h>
diff --git a/libp2p/Common.h b/libp2p/Common.h
index 378064e7d..96b8b9683 100644
--- a/libp2p/Common.h
+++ b/libp2p/Common.h
@@ -203,3 +203,26 @@ struct Node
 /// Simple stream output for a NodeIPEndpoint.
 std::ostream& operator<<(std::ostream& _out, dev::p2p::NodeIPEndpoint const& _ep);
 }
+
+/// std::hash for asio::adress
+namespace std
+{
+
+template <> struct hash<bi::address>
+{
+	size_t operator()(bi::address const& _a) const
+	{
+		if (_a.is_v4())
+			return _a.to_v4().to_ulong();
+		if (_a.is_v6())
+		{
+			auto const& range = _a.to_v6().to_bytes();
+			return boost::hash_range(range.begin(), range.end());
+		}
+		if (_a.is_unspecified())
+			return static_cast<size_t>(0x3487194039229152ul);  // Some random value
+		return std::hash<std::string>()(_a.to_string());
+	}
+};
+
+}
diff --git a/libp2p/Host.h b/libp2p/Host.h
index 41f4d1e72..b9af0e8b0 100644
--- a/libp2p/Host.h
+++ b/libp2p/Host.h
@@ -227,7 +227,7 @@ private:
 	std::shared_ptr<NodeTable> m_nodeTable;									///< Node table (uses kademlia-like discovery).
 
 	/// Shared storage of Peer objects. Peers are created or destroyed on demand by the Host. Active sessions maintain a shared_ptr to a Peer;
-	std::map<NodeId, std::shared_ptr<Peer>> m_peers;
+	std::unordered_map<NodeId, std::shared_ptr<Peer>> m_peers;
 	
 	/// Peers we try to connect regardless of p2p network.
 	std::set<NodeId> m_requiredPeers;
@@ -235,7 +235,7 @@ private:
 
 	/// The nodes to which we are currently connected. Used by host to service peer requests and keepAlivePeers and for shutdown. (see run())
 	/// Mutable because we flush zombie entries (null-weakptrs) as regular maintenance from a const method.
-	mutable std::map<NodeId, std::weak_ptr<Session>> m_sessions;
+	mutable std::unordered_map<NodeId, std::weak_ptr<Session>> m_sessions;
 	mutable RecursiveMutex x_sessions;
 	
 	std::list<std::weak_ptr<RLPXHandshake>> m_connecting;					///< Pending connections.
diff --git a/libp2p/Network.cpp b/libp2p/Network.cpp
index 847e6a42d..d8ab90a20 100644
--- a/libp2p/Network.cpp
+++ b/libp2p/Network.cpp
@@ -154,12 +154,12 @@ int Network::tcp4Listen(bi::tcp::acceptor& _acceptor, NetworkPreferences const&
 			_acceptor.bind(endpoint);
 			_acceptor.listen();
 			retport = _acceptor.local_endpoint().port();
+			assert(retport == _netPrefs.listenPort);
 		}
 		catch (...)
 		{
 			clog(NetWarn) << "Couldn't start accepting connections on host. Failed to accept socket.\n" << boost::current_exception_diagnostic_information();
 		}
-		assert(retport == _netPrefs.listenPort);
 		return retport;
 	}
 	return retport;
diff --git a/libp2p/NodeTable.cpp b/libp2p/NodeTable.cpp
index 42f1cad02..7a68cae10 100644
--- a/libp2p/NodeTable.cpp
+++ b/libp2p/NodeTable.cpp
@@ -232,7 +232,7 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 	unsigned head = distance(m_node.id, _target);
 	unsigned tail = head == 0 ? lastBin : (head - 1) % s_bins;
 	
-	map<unsigned, list<shared_ptr<NodeEntry>>> found;
+	unordered_multimap<unsigned, shared_ptr<NodeEntry>> found;
 	unsigned count = 0;
 	
 	// if d is 0, then we roll look forward, if last, we reverse, else, spread from d
@@ -244,7 +244,7 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 				if (auto p = n.lock())
 				{
 					if (count < s_bucketSize)
-						found[distance(_target, p->id)].push_back(p);
+						found.insert(make_pair(distance(_target, p->id), p));
 					else
 						break;
 				}
@@ -254,7 +254,7 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 					if (auto p = n.lock())
 					{
 						if (count < s_bucketSize)
-							found[distance(_target, p->id)].push_back(p);
+							found.insert(make_pair(distance(_target, p->id), p));
 						else
 							break;
 					}
@@ -271,7 +271,7 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 				if (auto p = n.lock())
 				{
 					if (count < s_bucketSize)
-						found[distance(_target, p->id)].push_back(p);
+						found.insert(make_pair(distance(_target, p->id), p));
 					else
 						break;
 				}
@@ -285,7 +285,7 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 				if (auto p = n.lock())
 				{
 					if (count < s_bucketSize)
-						found[distance(_target, p->id)].push_back(p);
+						found.insert(make_pair(distance(_target, p->id), p));
 					else
 						break;
 				}
@@ -293,10 +293,9 @@ vector<shared_ptr<NodeEntry>> NodeTable::nearestNodeEntries(NodeId _target)
 		}
 	
 	vector<shared_ptr<NodeEntry>> ret;
-	for (auto& nodes: found)
-		for (auto n: nodes.second)
-			if (n->endpoint.isAllowed())
-				ret.push_back(n);
+		for (auto n: found)
+			if (n.second->endpoint.isAllowed())
+				ret.push_back(n.second);
 	return move(ret);
 }
 
diff --git a/libp2p/NodeTable.h b/libp2p/NodeTable.h
index 95028db2b..f09e27857 100644
--- a/libp2p/NodeTable.h
+++ b/libp2p/NodeTable.h
@@ -80,7 +80,7 @@ protected:
 
 	Mutex x_events;
 	std::list<NodeId> m_nodeEventHandler;
-	std::map<NodeId, NodeTableEventType> m_events;
+	std::unordered_map<NodeId, NodeTableEventType> m_events;
 };
 
 class NodeTable;
@@ -254,32 +254,32 @@ private:
 	/// Purges and pings nodes for any buckets which haven't been touched for c_bucketRefresh seconds.
 	void doRefreshBuckets(boost::system::error_code const& _ec);
 
-	std::unique_ptr<NodeTableEventHandler> m_nodeEventHandler;	///< Event handler for node events.
+	std::unique_ptr<NodeTableEventHandler> m_nodeEventHandler;		///< Event handler for node events.
 
-	Node m_node;												///< This node.
-	Secret m_secret;											///< This nodes secret key.
+	Node m_node;													///< This node.
+	Secret m_secret;												///< This nodes secret key.
 
-	mutable Mutex x_nodes;									///< LOCK x_state first if both locks are required. Mutable for thread-safe copy in nodes() const.
-	std::map<NodeId, std::shared_ptr<NodeEntry>> m_nodes;		///< Nodes
+	mutable Mutex x_nodes;											///< LOCK x_state first if both locks are required. Mutable for thread-safe copy in nodes() const.
+	std::unordered_map<NodeId, std::shared_ptr<NodeEntry>> m_nodes;	///< Nodes
 
-	mutable Mutex x_state;									///< LOCK x_state first if both x_nodes and x_state locks are required.
-	std::array<NodeBucket, s_bins> m_state;					///< State of p2p node network.
+	mutable Mutex x_state;											///< LOCK x_state first if both x_nodes and x_state locks are required.
+	std::array<NodeBucket, s_bins> m_state;							///< State of p2p node network.
 
-	Mutex x_evictions;										///< LOCK x_nodes first if both x_nodes and x_evictions locks are required.
-	std::deque<EvictionTimeout> m_evictions;					///< Eviction timeouts.
+	Mutex x_evictions;												///< LOCK x_nodes first if both x_nodes and x_evictions locks are required.
+	std::deque<EvictionTimeout> m_evictions;						///< Eviction timeouts.
 	
-	Mutex x_pubkDiscoverPings;								///< LOCK x_nodes first if both x_nodes and x_pubkDiscoverPings locks are required.
-	std::map<bi::address, TimePoint> m_pubkDiscoverPings;		///< List of pending pings where node entry wasn't created due to unkown pubk.
+	Mutex x_pubkDiscoverPings;										///< LOCK x_nodes first if both x_nodes and x_pubkDiscoverPings locks are required.
+	std::unordered_map<bi::address, TimePoint> m_pubkDiscoverPings;	///< List of pending pings where node entry wasn't created due to unkown pubk.
 
 	Mutex x_findNodeTimeout;
-	std::list<NodeIdTimePoint> m_findNodeTimeout;				///< Timeouts for pending Ping and FindNode requests.
+	std::list<NodeIdTimePoint> m_findNodeTimeout;					///< Timeouts for pending Ping and FindNode requests.
 	
-	ba::io_service& m_io;										///< Used by bucket refresh timer.
-	std::shared_ptr<NodeSocket> m_socket;						///< Shared pointer for our UDPSocket; ASIO requires shared_ptr.
-	NodeSocket* m_socketPointer;								///< Set to m_socket.get(). Socket is created in constructor and disconnected in destructor to ensure access to pointer is safe.
+	ba::io_service& m_io;											///< Used by bucket refresh timer.
+	std::shared_ptr<NodeSocket> m_socket;							///< Shared pointer for our UDPSocket; ASIO requires shared_ptr.
+	NodeSocket* m_socketPointer;									///< Set to m_socket.get(). Socket is created in constructor and disconnected in destructor to ensure access to pointer is safe.
 
-	boost::asio::deadline_timer m_bucketRefreshTimer;			///< Timer which schedules and enacts bucket refresh.
-	boost::asio::deadline_timer m_evictionCheckTimer;			///< Timer for handling node evictions.
+	boost::asio::deadline_timer m_bucketRefreshTimer;				///< Timer which schedules and enacts bucket refresh.
+	boost::asio::deadline_timer m_evictionCheckTimer;				///< Timer for handling node evictions.
 };
 
 inline std::ostream& operator<<(std::ostream& _out, NodeTable const& _nodeTable)
diff --git a/mix/ClientModel.cpp b/mix/ClientModel.cpp
index fa5ec1c27..c558c71f3 100644
--- a/mix/ClientModel.cpp
+++ b/mix/ClientModel.cpp
@@ -211,7 +211,7 @@ void ClientModel::setupState(QVariantMap _state)
 	QVariantList stateContracts = _state.value("contracts").toList();
 	QVariantList transactions = _state.value("transactions").toList();
 
-	map<Address, Account> accounts;
+	unordered_map<Address, Account> accounts;
 	std::vector<KeyPair> userAccounts;
 
 	for (auto const& b: stateAccounts)
@@ -284,7 +284,7 @@ void ClientModel::setupState(QVariantMap _state)
 	executeSequence(transactionSequence, accounts, Secret(_state.value("miner").toMap().value("secret").toString().toStdString()));
 }
 
-void ClientModel::executeSequence(vector<TransactionSettings> const& _sequence, std::map<Address, Account> const& _accounts, Secret const& _miner)
+void ClientModel::executeSequence(vector<TransactionSettings> const& _sequence, std::unordered_map<Address, Account> const& _accounts, Secret const& _miner)
 {
 	if (m_running)
 	{
@@ -551,7 +551,7 @@ QVariant ClientModel::formatValue(SolidityType const& _type, u256 const& _value)
 	return res;
 }
 
-QVariant ClientModel::formatStorageValue(SolidityType const& _type, map<u256, u256> const& _storage, unsigned _offset, u256 const& _slot)
+QVariant ClientModel::formatStorageValue(SolidityType const& _type, unordered_map<u256, u256> const& _storage, unsigned _offset, u256 const& _slot)
 {
 	u256 slot = _slot;
 	QVariantList values;
diff --git a/mix/ClientModel.h b/mix/ClientModel.h
index 91b66c76c..b88ae8511 100644
--- a/mix/ClientModel.h
+++ b/mix/ClientModel.h
@@ -220,14 +220,14 @@ private:
 	RecordLogEntry* lastBlock() const;
 	QVariantMap contractAddresses() const;
 	QVariantList gasCosts() const;
-	void executeSequence(std::vector<TransactionSettings> const& _sequence, std::map<Address, dev::eth::Account> const& _accounts, Secret const& _miner);
+	void executeSequence(std::vector<TransactionSettings> const& _sequence, std::unordered_map<Address, dev::eth::Account> const& _accounts, Secret const& _miner);
 	dev::Address deployContract(bytes const& _code, TransactionSettings const& _tr = TransactionSettings());
 	void callContract(Address const& _contract, bytes const& _data, TransactionSettings const& _tr);
 	void onNewTransaction();
 	void onStateReset();
 	void showDebuggerForTransaction(ExecutionResult const& _t);
 	QVariant formatValue(SolidityType const& _type, dev::u256 const& _value);
-	QVariant formatStorageValue(SolidityType const& _type, std::map<dev::u256, dev::u256> const& _storage, unsigned _offset, dev::u256 const& _slot);
+	QVariant formatStorageValue(SolidityType const& _type, std::unordered_map<dev::u256, dev::u256> const& _storage, unsigned _offset, dev::u256 const& _slot);
 
 	std::atomic<bool> m_running;
 	std::atomic<bool> m_mining;
diff --git a/mix/MachineStates.h b/mix/MachineStates.h
index afd2b990a..2a88d83bf 100644
--- a/mix/MachineStates.h
+++ b/mix/MachineStates.h
@@ -50,7 +50,7 @@ namespace mix
 		dev::u256s stack;
 		dev::bytes memory;
 		dev::bigint gasCost;
-		std::map<dev::u256, dev::u256> storage;
+		std::unordered_map<dev::u256, dev::u256> storage;
 		std::vector<unsigned> levels;
 		unsigned codeIndex;
 		unsigned dataIndex;
diff --git a/mix/MixClient.cpp b/mix/MixClient.cpp
index b1d8f889e..1f309c5af 100644
--- a/mix/MixClient.cpp
+++ b/mix/MixClient.cpp
@@ -69,14 +69,14 @@ bytes MixBlockChain::createGenesisBlock(h256 _stateRoot)
 MixClient::MixClient(std::string const& _dbPath):
 	m_dbPath(_dbPath)
 {
-	resetState(std::map<Address, Account>());
+	resetState(std::unordered_map<Address, Account>());
 }
 
 MixClient::~MixClient()
 {
 }
 
-void MixClient::resetState(std::map<Address, Account> const& _accounts,  Secret const& _miner)
+void MixClient::resetState(std::unordered_map<Address, Account> const& _accounts,  Secret const& _miner)
 {
 	WriteGuard l(x_state);
 	Guard fl(x_filtersWatches);
diff --git a/mix/MixClient.h b/mix/MixClient.h
index 182e333c2..99637720a 100644
--- a/mix/MixClient.h
+++ b/mix/MixClient.h
@@ -48,7 +48,7 @@ public:
 	MixClient(std::string const& _dbPath);
 	virtual ~MixClient();
 	/// Reset state to the empty state with given balance.
-	void resetState(std::map<dev::Address, dev::eth::Account> const& _accounts,  Secret const& _miner = Secret());
+	void resetState(std::unordered_map<dev::Address, dev::eth::Account> const& _accounts,  Secret const& _miner = Secret());
 	void mine();
 	ExecutionResult lastExecution() const;
 	ExecutionResult execution(unsigned _index) const;
diff --git a/test/TestHelper.cpp b/test/TestHelper.cpp
index 144a1a286..96e11e02c 100644
--- a/test/TestHelper.cpp
+++ b/test/TestHelper.cpp
@@ -305,7 +305,7 @@ void ImportTest::checkExpectedState(State const& _stateExpect, State const& _sta
 
 			if (addressOptions.m_bHasStorage)
 			{
-				map<u256, u256> stateStorage = _statePost.storage(a.first);
+				unordered_map<u256, u256> stateStorage = _statePost.storage(a.first);
 				for (auto const& s: _stateExpect.storage(a.first))
 					CHECK(stateStorage[s.first] == s.second,
 							"Check State: " << a.first <<  ": incorrect storage [" << s.first << "] = " << toHex(stateStorage[s.first]) << ", expected [" << s.first << "] = " << toHex(s.second));
diff --git a/test/fuzzTesting/checkRandomStateTest.cpp b/test/fuzzTesting/checkRandomStateTest.cpp
index 719798620..01366cd4d 100644
--- a/test/fuzzTesting/checkRandomStateTest.cpp
+++ b/test/fuzzTesting/checkRandomStateTest.cpp
@@ -173,7 +173,7 @@ bool doStateTest(mValue& _v)
 				}
 
 				//checkStorage(importer.m_statePost.storage(expectedAddr), theState.storage(expectedAddr), expectedAddr);
-				map<u256, u256> _resultStore = theState.storage(expectedAddr);
+				unordered_map<u256, u256> _resultStore = theState.storage(expectedAddr);
 
 				for (auto&& expectedStorePair : importer.m_statePost.storage(expectedAddr))
 				{
diff --git a/test/libethereum/state.cpp b/test/libethereum/state.cpp
index 93f7498b8..b682056ee 100644
--- a/test/libethereum/state.cpp
+++ b/test/libethereum/state.cpp
@@ -99,7 +99,7 @@ void doStateTests(json_spirit::mValue& v, bool _fillin)
 			ImportTest::checkExpectedState(importer.m_statePost, theState);
 			auto expectedAddrs = importer.m_statePost.addresses();
 			auto resultAddrs = theState.addresses();
-			checkAddresses<map<Address, u256> >(expectedAddrs, resultAddrs);
+			checkAddresses(expectedAddrs, resultAddrs);
 #endif
 			BOOST_CHECK_MESSAGE(theState.rootHash() == h256(o["postStateRoot"].get_str()), "wrong post state root");
 		}