#include <windows.h>
#include <stdio.h>

typedef unsigned __int64 MeU64;

/* Queries clock counter */
unsigned __int64 __declspec(naked)
ReadTsc(void){
    __asm
    {
        pushad
            cpuid
            popad
            rdtsc
            ret
    }
}

int main()
{
    MeU64 start,finish;
    LARGE_INTEGER perfFreq;
    LARGE_INTEGER perfCount;
    LARGE_INTEGER perfInitCount;
    
    if(!QueryPerformanceFrequency(&perfFreq))
        return 1; // You're pretty shafted if this happens :)
    
    QueryPerformanceCounter(&perfInitCount);
    perfCount = perfInitCount;
    
    start = ReadTsc();
    
    while(perfCount.QuadPart - perfInitCount.QuadPart < perfFreq.QuadPart) 
        QueryPerformanceCounter(&perfCount);
    
    finish = ReadTsc();    
    MeU64 m_clockTicksPerSec = finish - start;
    UINT mhz = (UINT)(m_clockTicksPerSec/1000000);

    printf("CPU is approx %dMHz\n", mhz);
    return 0;
}