两个获取CPU频率的代码断

1通过注册表

CString ProcSpeedRead()
{
CString sMHz;
char Buffer[_MAX_PATH];
DWORD BufSize = _MAX_PATH;
DWORD dwMHz = _MAX_PATH;
HKEY hKey;

// open the key where the proc speed is hidden:
long lError = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
                           "HARDWARE//DESCRIPTION//System//CentralProcessor//0",
                            0,
                            KEY_READ,
                            &hKey);
   
    if(lError != ERROR_SUCCESS)
      {// if the key is not found, tell the user why:
           FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM,
                         NULL,
                         lError,
                         0,
                         Buffer,
                         _MAX_PATH,
                         0);
               AfxMessageBox(Buffer);
           return "N/A";
       }

        // query the key:
        RegQueryValueEx(hKey, "~MHz", NULL, NULL, (LPBYTE) &dwMHz, &BufSize);

    // convert the DWORD to a CString:
    sMHz.Format("%i", dwMHz);

return sMHz;
}

2通过时钟循环与高精度计数器计算（非Inter处理器，例如AMD请更改RdTSC宏）

float CGettheProcessorSpeedDlg::ProcSpeedCalc()
{
/*
RdTSC:
It's the Pentium instruction "ReaD Time Stamp Counter". It measures the
number of clock cycles that have passed since the processor was reset, as a
64-bit number. That's what the _emit lines do.*/
#define RdTSC __asm _emit 0x0f __asm _emit 0x31

// variables for the clock-cycles:
__int64 cyclesStart = 0, cyclesStop = 0;
// variables for the High-Res Preformance Counter:
unsigned __int64 nCtr = 0, nFreq = 0, nCtrStop = 0;

    // retrieve performance-counter frequency per second:
    if(!QueryPerformanceFrequency((LARGE_INTEGER *) &nFreq)) return 0;

    // retrieve the current value of the performance counter:
    QueryPerformanceCounter((LARGE_INTEGER *) &nCtrStop);

    // add the frequency to the counter-value:
    nCtrStop += nFreq;

    _asm
        {// retrieve the clock-cycles for the start value:
            RdTSC
            mov DWORD PTR cyclesStart, eax
            mov DWORD PTR [cyclesStart + 4], edx
        }

        do{// retrieve the value of the performance counter until 1 sec has gone by:
             QueryPerformanceCounter((LARGE_INTEGER *) &nCtr);
          }while (nCtr < nCtrStop);

    _asm
        {// retrieve again the clock-cycles after 1 sec. has gone by:
            RdTSC
            mov DWORD PTR cyclesStop, eax
            mov DWORD PTR [cyclesStop + 4], edx
        }

// stop-start is speed in Hz divided by 1,000,000 is speed in MHz
return    ((float)cyclesStop-(float)cyclesStart) / 1000000;
}

----摘自 CodeProject 作者Thomas Latuske

实例工程下载地址：

http://www.codeproject.com/useritems/Processor_Speed/Processor_Speed_demo.zip