diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 62712d5f6..e2f8d52d1 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -1616,7 +1616,7 @@ namespace libtorrent
 
 #ifndef NDEBUG
 		check_postcondition post_checker_(t);
-#if !defined TORRENT_DISABLE_INVARIANT_CHECKS
+#if !defined TORRENT_DISABLE_INVARIANT_CHECKS && defined TORRENT_EXPENSIVE_INVARIANT_CHECKS
 		t->check_invariant();
 #endif
 #endif
@@ -1791,7 +1791,8 @@ namespace libtorrent
 
 		TORRENT_ASSERT(picker.num_peers(block_finished) == 0);
 
-#if !defined NDEBUG && !defined TORRENT_DISABLE_INVARIANT_CHECKS
+#if !defined NDEBUG && !defined TORRENT_DISABLE_INVARIANT_CHECKS \
+	&& defined TORRENT_EXPENSIVE_INVARIANT_CHECKS
 		t->check_invariant();
 #endif
 		request_a_block(*t, *this);
diff --git a/src/piece_picker.cpp b/src/piece_picker.cpp
index c8b5d8d99..8935609fa 100644
--- a/src/piece_picker.cpp
+++ b/src/piece_picker.cpp
@@ -122,7 +122,9 @@ namespace libtorrent
 
 	void piece_picker::piece_info(int index, piece_picker::downloading_piece& st) const
 	{
+#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
 		TORRENT_PIECE_PICKER_INVARIANT_CHECK;
+#endif
 		
 		TORRENT_ASSERT(index >= 0);
 		TORRENT_ASSERT(index < int(m_piece_map.size()));
@@ -1312,7 +1314,9 @@ namespace libtorrent
 		// only one of rarest_first and sequential can be set.
 		TORRENT_ASSERT(bool(options & rarest_first)
 			+ bool(options & sequential) <= 1);
+#ifdef TORRENT_EXPENSIVE_INVARIANT_CHECKS
 		TORRENT_PIECE_PICKER_INVARIANT_CHECK;
+#endif
 		TORRENT_ASSERT(num_blocks > 0);
 		TORRENT_ASSERT(pieces.size() == m_piece_map.size());