diff --git a/common/rfb/ComparingUpdateTracker.cxx b/common/rfb/ComparingUpdateTracker.cxx
index 43287e0..1c2bd38 100644
--- a/common/rfb/ComparingUpdateTracker.cxx
+++ b/common/rfb/ComparingUpdateTracker.cxx
@@ -35,7 +35,7 @@
 }
 
 
-#define BLOCK_SIZE 16
+#define BLOCK_SIZE 64
 
 bool ComparingUpdateTracker::compare()
 {