diff --git a/src/tt.cpp b/src/tt.cpp
index 862842f2..770e38b7 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -34,7 +34,7 @@
 #endif
 
 // This is the number of TTEntry slots for each position
-static const int ClusterSize = 5;
+static const int ClusterSize = 4;
 
 // The main transposition table
 TranspositionTable TT;
diff --git a/src/tt.h b/src/tt.h
index 0b7ccbe8..e838b090 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -70,6 +70,7 @@ private:
   uint32_t data;
   int16_t value_;
   int16_t depth_;
+  uint32_t pad_to_16_bytes;
 };
 
 /// The transposition table class.  This is basically just a huge array