I am not certain why there's a substantial difference for idling CPU frequency between W8.1 and W7. My PC runs both OS in dual-boot mode, controlled by EUFI "F12" key. Other than both OS having it's own SSD drive, the hardware is identical.

Both OS used HWMonitor, v1.27.0, initially just to see the CPU temperature that lead me to the CPU frequency differences.

The HWMonitor for Windows 7 shows this:

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The same for Windows 8.1 shows this:

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And no, there isn't anything pegging the CPU, W8.1 task manager shows low CPU utilization around at the time the HWMonitor image had been captured:

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The CPU speed/frequency is actually confirmed by the task manager. Is speedstep broken in Windows 8.1, or HWMonitor is not accurate?