为什么这种获取cpu利用率的方法产生的结果比任务管理器的结果低2倍?

我正在使用以下方法检测CPU利用率:

#include "pch.h"
#include <iostream>
#include <Windows.h>

int get_CPU_Usage(void);


int main()
{
    COORD c = {0};
    HANDLE hStdOut = ::GetStdHandle(STD_OUTPUT_HANDLE);

    for(;; ::Sleep(500))
    {
        ::SetConsoleCursorPosition(hStdOut, c);
        wprintf(L"Current CPU usage: %d%%\t\t\n", get_CPU_Usage());
    }

}




int get_CPU_Usage(void)
{
    //RETURN: = CPU Usage in percent [0 - 100], or
    //        = -1 if error
    int nRes = -1;

    //Run system function
    FILETIME ftIdle, ftKrnl, ftUsr;
    if(::GetSystemTimes(&ftIdle, &ftKrnl, &ftUsr))
    {
        //Now calculate value
        static BOOL bUsedOnce = FALSE;
        static ULONGLONG uOldIdle = 0;
        static ULONGLONG uOldKrnl = 0;
        static ULONGLONG uOldUsr = 0;

        ULONGLONG uIdle = ((ULONGLONG)ftIdle.dwHighDateTime << 32) | ftIdle.dwLowDateTime;
        ULONGLONG uKrnl = ((ULONGLONG)ftKrnl.dwHighDateTime << 32) | ftKrnl.dwLowDateTime;
        ULONGLONG uUsr = ((ULONGLONG)ftUsr.dwHighDateTime << 32) | ftUsr.dwLowDateTime;

        //Only if we have previous values
        if(bUsedOnce)
        {
            ULONGLONG uDiffIdle = uIdle - uOldIdle;
            ULONGLONG uDiffKrnl = uKrnl - uOldKrnl;
            ULONGLONG uDiffUsr = uUsr - uOldUsr;

            if(uDiffKrnl + uDiffUsr)
            {
                //Calculate percentage
                nRes = (int)((uDiffKrnl + uDiffUsr - uDiffIdle) * 100 / (uDiffKrnl + uDiffUsr));

                //Check value and correct it (Just in case)
                if(nRes < 0)
                    nRes = 0;
                else if(nRes > 100)
                    nRes = 100;
            }
        }

        //Remember data
        bUsedOnce = TRUE;
        uOldIdle = uIdle;
        uOldKrnl = uKrnl;
        uOldUsr = uUsr;
    }

    return nRes;
}

它以前在我运行windows 8.1的旧计算机上提供类似的阅读,但现在当我在这个桌面上运行它时 Intel(R) Core(TM) i9-7940X CPU @ 3.10GHz 在Windows 10 Pro上,它给出的结果似乎比任务管理器显示的结果低2倍:

用截图很难捕捉到它,但从上面的代码中,我绝对可以看到更低的数字。

所以我想知道,为什么如此悬殊?

我正在测试的CPU有14个物理核和28个逻辑核。这会不会影响 GetSystemTimes 功能?