diff --git a/src/liblzma/common/index.c b/src/liblzma/common/index.c
index 3941e28..ddb9d36 100644
--- a/src/liblzma/common/index.c
+++ b/src/liblzma/common/index.c
@@ -18,7 +18,7 @@
 ///
 /// This should be big enough to avoid making lots of tiny allocations
 /// but small enough to avoid too much unused memory at once.
-#define INDEX_GROUP_SIZE 500
+#define INDEX_GROUP_SIZE 512
 
 
 /// \brief      How many Records can be allocated at once at maximum