diff --git a/programs/bench.c b/programs/bench.c
index 8ab66d92..1892ddd6 100644
--- a/programs/bench.c
+++ b/programs/bench.c
@@ -83,7 +83,7 @@
 #define MB *(1 <<20)
 #define GB *(1U<<30)
 
-static const size_t maxMemory = sizeof(size_t)==4 ? (2 GB - 64 MB) : (size_t)(8ULL GB);
+static const size_t maxMemory = sizeof(size_t)==4  ?  (2 GB - 64 MB) : (size_t)(1ULL << (sizeof(size_t)*8-31));
 #define DEFAULT_CHUNKSIZE   (4 MB)
 
 static U32 g_compressibilityDefault = 50;