diff --git a/c/windows.c b/c/windows.c
index 858557d..5482878 100644
--- a/c/windows.c
+++ b/c/windows.c
@@ -3,9 +3,12 @@
 #include <string.h>
 #include <windows.h>
 #include <psapi.h>
+#include <intrin.h>
 
 #include "info.h"
 
+#pragma intrinsic(__rdtsc)
+
 #define LEN 20
 #define MAXPROCESSES 1024
 static const char *os_type = "Windows";