diff --git a/mpn/x86_64/core2/penryn/gmp-mparam.h b/mpn/x86_64/core2/penryn/gmp-mparam.h
index 888db254..78041f07 100644
--- a/mpn/x86_64/core2/penryn/gmp-mparam.h
+++ b/mpn/x86_64/core2/penryn/gmp-mparam.h
@@ -13,9 +13,9 @@
 
 #define POWM_THRESHOLD                   64
 
-#define GCD_ACCEL_THRESHOLD              24 
-#define GCD_THRESHOLD                   500 
-#define GCDEXT_THRESHOLD                800
+#define GCD_ACCEL_THRESHOLD              24
+#define GCD_THRESHOLD                   502
+#define GCDEXT_THRESHOLD                781
 #define JACOBI_BASE_METHOD                1
 
 #define DIVREM_1_NORM_THRESHOLD       MP_SIZE_T_MAX  /* never */