C#：如何找到 CPU 的当前时钟速度？

Question

Currently working on creating a sorts of "task manager" in c#/wpf. I've searched around but haven't found a solution to my problem.

I am trying to retrieve the CURRENT clock speed of one's CPU (not utilization, base, min/max). I have tried using ManagementObjects, but "CurrentClockSpeed" is always giving a fixed value of 3400, or 3.4GHz, which is the stock max speed of the CPU. I have tried many times and it gives me the same answer, so it isn't just a coincidence i think.

    ManagementObject Mo = new ManagementObject("Win32_Processor.DeviceID='CPU0'");
        uint sp = (uint)(Mo["CurrentClockSpeed"]);
        System.Threading.Thread.Sleep(1000);
        sp = (uint)(Mo["CurrentClockSpeed"]);
        Mo.Dispose(); //return and such later in the code

Any suggestions on how to fix this issue (I am not bound to using ManagementObjects, I have OpenHardwareMonitor, and can use other packages if need be) are appreciated.

Answer 1

On the WMI object the MaxClockSpeed property gives you the maximum speed of the core, which should be constant. The CurrentClockSpeed property tells you the current clock speed. This may be leess than the MaxClockSpeed dues to cpu throttling.

I believe you can disable throttling at the BIOS level or via the Windows power management control panel applet, so it's possible that *CurrentClockSpeed** will always be the same as MaxClockSpeed .

Answer 2

I had the same question eight years before you did. WMI does not return the real current clock speed, and this appears to still be the case, at least through Windows 10.

For whatever reason, WMI only returns the base clock speed as the value for both maximum and current clock speed. It's not an issue of CPU support; CPU-Z is able to report the correct clock speed, as does Task Manager. It's a piece of data the OS has at its disposal, but doesn't make readily available. There's probably a way to get the exact value from the CPU using C++, but lots of devs aren't fluent in that language.

This awesome answer worked perfectly for me! I finally got this application working properly, after starting (and abandoning) it in 2010.

(PS This doesn't work in Windows 7; it seems the perfmon counter used didn't exist back then.)

Answer 3

When running the code at an Intel CPU with access to MSRs then you may evaluate the current CPU frequency from IA32_MPERF (0xE7) TSC Frequency Clock Counter and IA32_APERF (0xE8) Actual Performance Clock Counter.

aperf_t1 = read_aperf();
mperf_t1 = read_mperf();

sleep(1);   

aperf_t2 = read_aperf();
mperf_t2 = read_mperf();

printf("CPU freq: %f [Hz]\n", ((aperf_t2-aperf_t1) / (double)(mperf_t2-mperf_t1)) * nominal_freq);