diff --git a/src/hnsw.h b/src/hnsw.h
index 76c7c6c..3e8bdc2 100644
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -36,7 +36,7 @@
 #define HNSW_DEFAULT_M	16
 #define HNSW_MIN_M	2
 #define HNSW_MAX_M		100
-#define HNSW_DEFAULT_EF_CONSTRUCTION	40
+#define HNSW_DEFAULT_EF_CONSTRUCTION	64
 #define HNSW_MIN_EF_CONSTRUCTION	4
 #define HNSW_MAX_EF_CONSTRUCTION		1000
 #define HNSW_DEFAULT_EF_SEARCH	40