Windows 8 overclocking: HWBot voids all results

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Windows 8 has been out for almost a year and its become rather popular with overclockers thanks to greater stability and faster boot times. However, the OS required a complete kernel re-write, which changed a lot of things around. Including, it seems, a very crucial element called the system clock.

HWBot has announced that they are declaring all results obtained from hardware running Microsoft’s Windows 8 to be null and void. The system clock generator, or “real time clock” (RTC) in the OS is faulty, allowing benchmarkers with the right know-how to tweak their clock speeds to alter their scores and move up the rankings. Benchmarks rely on the RTC value to reference and validate benchmark times.

To elaborate, the RTC is the measure that all programs depend on. Windows records system time according to the frequency of a vibrating crystal and Windows 8 changed how the system records time to save battery life for notebooks and tablets. Because the kernel is also shared on Windows Phone and Windows RT, Microsoft had to go with a one-size-fits-all approach, which groups together system calls that can, for example, change the time and change your idle state, to save on power.

But once overclocked, especially if you’re on the Intel Haswell platform and have opted to choose a 122MHz strap speed for the BLCK, that system clock generator’s behaviour alters slightly. Results obtained at stock speeds are fine, but overclocked ones are not. The system clock would then run faster than it would in real-time, decreasing the time that the machine records to have passed during the banchmark.

HWBot admins discovered that a flaw in the generator allowed one to underclock the system slightly to mis-time the clock generator, removing the performance deficit from underclocking in benchmarks and boosting their scores. The results are quite dramatic.

HWBot submission scores after tweaking the system clock

HWBot submission scores after tweaking the system clock

HWBot’s admins have announced that they are removing all overclocked Windows 8 scores until further notice and are working to figure out a solution to the problem. For now, its advisable to do benchmarking on Windows 7 or Windows XP.

“As the result of weekend-time research, the HWBOT staff has decided to invalidate all benchmark records established with the Windows8 operating system. Due to severe validity problems with the Windows8 real time clock (“RTC”), benchmarks results achieved with Windows8 cannot be trusted. The main problem lies with the RTC being affected when over- or underclocking under the operating system. The operating system uses the RTC as reference clock, and benchmarks use it to reference (benchmark) time.”

Source: HWBot

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  • UltimateNinjaPandaDudeGuy

    Most things about Windows 8 is null and void…

  • The Rich

    Honestly, all of this was completely over my head/above my pay grade.

  • Wesley Fick

    Basically, before you boot into Windows, the BIOS checks the set time, which is matched to the vibrations of a quartz crystal that determines the system clock. That crystal’s vibration is controlled by the BLCK option in the BIOS. If you boot with the BLCK at a set ratio, like 130MHz, the system will keep track of time according to the frequency of that crystal.

    But if you’re now in Windows and use software overclocking options to change the BLCK ratio without rebooting, Windows will continue to run on the previous time setting. The problem occurs when underclocking the BLCK ratio, because benchmarks always use the new ratio, not the one the system booted with. That creates a difference in the time recorded to Windows and the benchmark.

    So you can run a benchmark that took X amount of time, underclock the BLCK by another amount (lets call it A), run the benchmark again, you end up with:

    X – A% = Y

    Y is the new reported time, which has been recorded at a different rate to Windows, but is registered as an improvement, boosting your scores even though nothing else has really changed.

  • The Rich

    Thanks Wesley for your epic response – the whole thing actually is a lot easier to understand now. At the very least, I can start to see now why this issue is, well, an issue in the overclocking community. Thanks man.

  • Ian Kemp

    This is only an issue with Intel processors, and only if the processor is running Windows 8. Hence all AMD processor benchmarks, and Intel processor benchmarks recorded on Windows 7 or lower, are still being accepted by HWBot.