diff --git a/src/system.h b/src/system.h
index 827df96..f39fff0 100644
--- a/src/system.h
+++ b/src/system.h
@@ -119,10 +119,12 @@ int strcasecmp (char const *, char const *);
 #include "propername.h"
 #include "version.h"
 
-/* Type used for fast comparison of several bytes at a time.  */
+/* Type used for fast comparison of several bytes at a time.
+   This used to be uintmax_t, but changing it to size_t
+   made plain 'cmp' 90% faster (GCC 4.8.1, x86).  */
 
 #ifndef word
-# define word uintmax_t
+# define word size_t
 #endif
 
 /* The integer type of a line number.  Since files are read into main