diff --git a/configure.ac b/configure.ac
index ca66216554..31074d7720 100644
--- a/configure.ac
+++ b/configure.ac
@@ -236,6 +236,12 @@ if test "x$CXXFLAGS_overridden" = "xno"; then
   AX_CHECK_COMPILE_FLAG([-Wunused-local-typedef],[CXXFLAGS="$CXXFLAGS -Wno-unused-local-typedef"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wdeprecated-register],[CXXFLAGS="$CXXFLAGS -Wno-deprecated-register"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wimplicit-fallthrough],[CXXFLAGS="$CXXFLAGS -Wno-implicit-fallthrough"],,[[$CXXFLAG_WERROR]])
+
+  # Check for optional instruction set support. Enabling these does _not_ imply that all code will
+  # be compiled with them, rather that specific objects/libs may use them after checking for runtime
+  # compatibility.
+  AX_CHECK_COMPILE_FLAG([-msse4.2],[[enable_sse42=yes; SSE42_CXXFLAGS="-msse4.2"]],,[[$CXXFLAG_WERROR]])
+
 fi
 CPPFLAGS="$CPPFLAGS -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS"
 
@@ -1114,6 +1120,7 @@ AM_CONDITIONAL([USE_QRCODE], [test x$use_qr = xyes])
 AM_CONDITIONAL([USE_LCOV],[test x$use_lcov = xyes])
 AM_CONDITIONAL([GLIBC_BACK_COMPAT],[test x$use_glibc_compat = xyes])
 AM_CONDITIONAL([HARDEN],[test x$use_hardening = xyes])
+AM_CONDITIONAL([ENABLE_SSE42],[test x$enable_sse42 = xyes])
 
 AC_DEFINE(CLIENT_VERSION_MAJOR, _CLIENT_VERSION_MAJOR, [Major version])
 AC_DEFINE(CLIENT_VERSION_MINOR, _CLIENT_VERSION_MINOR, [Minor version])
@@ -1146,6 +1153,7 @@ AC_SUBST(HARDENED_CPPFLAGS)
 AC_SUBST(HARDENED_LDFLAGS)
 AC_SUBST(PIC_FLAGS)
 AC_SUBST(PIE_FLAGS)
+AC_SUBST(SSE42_CXXFLAGS)
 AC_SUBST(LIBTOOL_APP_LDFLAGS)
 AC_SUBST(USE_UPNP)
 AC_SUBST(USE_QRCODE)
diff --git a/src/Makefile.am b/src/Makefile.am
index ae2eb29c94..a8b018a65b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -380,6 +380,7 @@ bitcoind_LDADD = \
   $(LIBBITCOIN_CONSENSUS) \
   $(LIBBITCOIN_CRYPTO) \
   $(LIBLEVELDB) \
+  $(LIBLEVELDB_SSE42) \
   $(LIBMEMENV) \
   $(LIBSECP256K1)
 
diff --git a/src/Makefile.bench.include b/src/Makefile.bench.include
index 3bcecab596..2b1f70b25b 100644
--- a/src/Makefile.bench.include
+++ b/src/Makefile.bench.include
@@ -39,6 +39,7 @@ bench_bench_bitcoin_LDADD = \
   $(LIBBITCOIN_CONSENSUS) \
   $(LIBBITCOIN_CRYPTO) \
   $(LIBLEVELDB) \
+  $(LIBLEVELDB_SSE42) \
   $(LIBMEMENV) \
   $(LIBSECP256K1) \
   $(LIBUNIVALUE)
diff --git a/src/Makefile.leveldb.include b/src/Makefile.leveldb.include
index 358f39cbef..b61088ef3a 100644
--- a/src/Makefile.leveldb.include
+++ b/src/Makefile.leveldb.include
@@ -4,12 +4,15 @@
 
 LIBLEVELDB_INT = leveldb/libleveldb.a
 LIBMEMENV_INT  = leveldb/libmemenv.a
+LIBLEVELDB_SSE42_INT  = leveldb/libleveldb_sse42.a
 
 EXTRA_LIBRARIES += $(LIBLEVELDB_INT)
 EXTRA_LIBRARIES += $(LIBMEMENV_INT)
+EXTRA_LIBRARIES += $(LIBLEVELDB_SSE42_INT)
 
 LIBLEVELDB += $(LIBLEVELDB_INT)
 LIBMEMENV += $(LIBMEMENV_INT)
+LIBLEVELDB_SSE42 = $(LIBLEVELDB_SSE42_INT)
 
 LEVELDB_CPPFLAGS += -I$(srcdir)/leveldb/include
 LEVELDB_CPPFLAGS += -I$(srcdir)/leveldb/helpers/memenv
@@ -135,3 +138,11 @@ leveldb_libmemenv_a_CPPFLAGS = $(leveldb_libleveldb_a_CPPFLAGS)
 leveldb_libmemenv_a_CXXFLAGS = $(leveldb_libleveldb_a_CXXFLAGS)
 leveldb_libmemenv_a_SOURCES =  leveldb/helpers/memenv/memenv.cc
 leveldb_libmemenv_a_SOURCES += leveldb/helpers/memenv/memenv.h
+
+leveldb_libleveldb_sse42_a_CPPFLAGS = $(leveldb_libleveldb_a_CPPFLAGS)
+leveldb_libleveldb_sse42_a_CXXFLAGS = $(leveldb_libleveldb_a_CXXFLAGS)
+if ENABLE_SSE42
+leveldb_libleveldb_sse42_a_CPPFLAGS += -DLEVELDB_PLATFORM_POSIX_SSE
+leveldb_libleveldb_sse42_a_CXXFLAGS += $(SSE42_CXXFLAGS)
+endif
+leveldb_libleveldb_sse42_a_SOURCES =  leveldb/port/port_posix_sse.cc
diff --git a/src/Makefile.qt.include b/src/Makefile.qt.include
index 48411f29ec..e4b64c1ca7 100644
--- a/src/Makefile.qt.include
+++ b/src/Makefile.qt.include
@@ -407,7 +407,7 @@ endif
 if ENABLE_ZMQ
 qt_bitcoin_qt_LDADD += $(LIBBITCOIN_ZMQ) $(ZMQ_LIBS)
 endif
-qt_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
+qt_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBLEVELDB_SSE42) $(LIBMEMENV) \
   $(BOOST_LIBS) $(QT_LIBS) $(QT_DBUS_LIBS) $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1) \
   $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS)
 qt_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
diff --git a/src/Makefile.qttest.include b/src/Makefile.qttest.include
index 391b9ebdf6..02f30bc952 100644
--- a/src/Makefile.qttest.include
+++ b/src/Makefile.qttest.include
@@ -60,7 +60,7 @@ if ENABLE_ZMQ
 qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_ZMQ) $(ZMQ_LIBS)
 endif
 qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) \
-  $(LIBMEMENV) $(BOOST_LIBS) $(QT_DBUS_LIBS) $(QT_TEST_LIBS) $(QT_LIBS) \
+  $(LIBLEVELDB_SSE42) $(LIBMEMENV) $(BOOST_LIBS) $(QT_DBUS_LIBS) $(QT_TEST_LIBS) $(QT_LIBS) \
   $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1) \
   $(EVENT_PTHREADS_LIBS) $(EVENT_LIBS)
 qt_test_test_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index ee1c11ff1f..cc255563f1 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -97,8 +97,8 @@ endif
 
 test_test_bitcoin_SOURCES = $(BITCOIN_TESTS) $(JSON_TEST_FILES) $(RAW_TEST_FILES)
 test_test_bitcoin_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) -I$(builddir)/test/ $(TESTDEFS) $(EVENT_CFLAGS)
-test_test_bitcoin_LDADD = $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
-  $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS) $(EVENT_PTHREADS_LIBS)
+test_test_bitcoin_LDADD = $(LIBBITCOIN_SERVER) $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CONSENSUS) $(LIBBITCOIN_CRYPTO) $(LIBUNIVALUE) \
+  $(LIBLEVELDB) $(LIBLEVELDB_SSE42) $(LIBMEMENV) $(BOOST_LIBS) $(BOOST_UNIT_TEST_FRAMEWORK_LIB) $(LIBSECP256K1) $(EVENT_LIBS) $(EVENT_PTHREADS_LIBS)
 test_test_bitcoin_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 if ENABLE_WALLET
 test_test_bitcoin_LDADD += $(LIBBITCOIN_WALLET)