Windows 8 bug on overclocked PCs found to alter benchmarks

By on August 20, 2013, 12:00 PM
microsoft, windows, pcs, windows 8, benchmark, overclocking, hwbot

A bug relating to the real-time clock has been discovered in Windows 8, which causes inaccurate benchmark results on over- or under-clocked systems. When a system's CPU clock frequency is adjusted from within the operating system, the software time-keeper no longer reports the time accurately, slowing down with an underclock and speeding up with an overclock.

The team at HWBOT did some research, finding that after a 6% CPU base clock decrease, the system time after five minutes lagged behind actual time by 18 seconds. In benchmarks this translated to a 5-7% score boost, when compared to a system of equal clock speed modified only through multiplier adjustment. Conversely, a base clock increase caused a score decrease in the same benchmarks.

After discovering the issue with Windows 8, HWBOT are no longer accepting benchmark results produced on the operating system, and are invalidating all previous Windows 8 results. There is the potential for overclockers to use the real-time clock bug to their advantage, and HWBOT want to ensure there is no potential for cheating. Windows 7 and previous operating systems are unaffected by the issue.

The real-time clock (RTC) is a hardware feature of many computer systems that keeps accurate track of the current time. In some low-cost and embedded systems, the RTC circuit is removed to save costs, and with Windows 8, Microsoft made several changes to preserve time-keeping compatibility with these machines. Now that it has been discovered that these changes affect benchmarks in some situations, Microsoft may have to look into patching the issue.




User Comments: 15

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misor misor said:

Is it really a windows 8 bug or the benchmarks themselves have bugs for not being able to cope up with changes due to 'underclock' and 'overclock'?

(bear with me; I'm not good at math and I barely understand those benchmarks)

3 people like this | Chazz said:

Is it really a windows 8 bug or the benchmarks themselves have bugs for not being able to cope up with changes due to 'underclock' and 'overclock'?

(bear with me; I'm not good at math and I barely understand those benchmarks)

I don't know details about this, but from what I gathered from this article its a windows issue. The clock fails to track time properly. Its being sped up(under clocked) or slowed down(overclocked). Id assume these benchmarks test performance over time, or track time taken to complete a task and rely on the system clock for this data. A lot of things depend on accurate time telling . I have windows 8 with a overclocked CPU, I did this from the bios though so I don't get this bug. So ya, seems to be an OS thing.

Guest said:

Not likely, since this would affect any timed benchmarks which used systemtime() to allot time to complete a task. In this case more time to complete a sequence of tasks would artificially boost scores for Win 8. Similar to if I asked 8 people to run as far as they can within ten minutes, but one of the runners is actually given 11 minutes to run instead. Assuming the person given extra time will actually use it to run further, he/she would seem to be able to run faster, since speed = distance/time. So the person with the highest distance run would be considered fastest; however the unequal timing would skew results in favor of the person given more time. Thus this method of measuring speed is flawed if time between systems cannot be accurately accounted for. Therefore this could potentially affect all such timed benchmarks in some way.

JC713 JC713 said:

This is a big hit for Win8.

5 people like this | amstech amstech, TechSpot Enthusiast, said:

Anyone who uses software to overclock thier PC is a poser anyways :P .

Chazz said:

This is a big hit for Win8.

I'm not quite sure what windows version you've used where you feel comfortable overclocking via windows, but you'd get more options via your bios. The last thing you'd want is less options if you like to overclock. I hope you don't flash bios via windows too.

2 people like this | Darth Shiv Darth Shiv said:

Is it really a windows 8 bug or the benchmarks themselves have bugs for not being able to cope up with changes due to 'underclock' and 'overclock'?

(bear with me; I'm not good at math and I barely understand those benchmarks)

Is it really a windows 8 bug or the benchmarks themselves have bugs for not being able to cope up with changes due to 'underclock' and 'overclock'?

(bear with me; I'm not good at math and I barely understand those benchmarks)

I don't know details about this, but from what I gathered from this article its a windows issue. The clock fails to track time properly. Its being sped up(under clocked) or slowed down(overclocked). Id assume these benchmarks test performance over time, or track time taken to complete a task and rely on the system clock for this data. A lot of things depend on accurate time telling . I have windows 8 with a overclocked CPU, I did this from the bios though so I don't get this bug. So ya, seems to be an OS thing.

I don't think they mean it is a bios vs OS overclock. They mean if the OS uses a software based clock for reporting system time. Most machines have hardware clocks but you can override the system time source to use a software clock. The software clock in Win8 is buggy.

E.g. if I have a hardware clock, I ask it "how much time has elapsed?". It tells me, accurately, what the time is.

If I have a software clock, I can't ask it what the time is because it doesn't track time. It tracks processor ticks. So to get the time, you need to know what the time was before, how many ticks have elapsed, what clock speed those ticks were at then you can work out the new time. If one of those numbers is inaccurate, your time calc is off.

1 person liked this | St1ckM4n St1ckM4n said:

I hope you don't flash bios via windows too.

No, I flash my BIOS via the BIOS.

1 person liked this | Darth Shiv Darth Shiv said:

No, I flash my BIOS via the BIOS.

Both methods I think prove that it doesn't matter where you flash your bios. Once it is "loaded", sounds like you can do anything to the bios firmware from any environment.

E.g. if you flash your bios in windows and it "fails" then don't restart your computer. Try flash it again (check your bios file isn't corrupt, redownload if necessary etc), cause while you haven't restarted, you can try to repair the firmware before it is needed (which is when your computer boots of course).

1 person liked this | Guest said:

Samsung showing MS some benchmark tricks?

JC713 JC713 said:

I'm not quite sure what windows version you've used where you feel comfortable overclocking via windows, but you'd get more options via your bios. The last thing you'd want is less options if you like to overclock. I hope you don't flash bios via windows too.

Right, this is only with desktop OCing. I forgot about that.

1 person liked this | misor misor said:

I'm not quite sure what windows version you've used where you feel comfortable overclocking via windows, but you'd get more options via your bios. The last thing you'd want is less options if you like to overclock. I hope you don't flash bios via windows too.

haha! I flashed my intel dh55tc mobo (with intel i3-530) in the windows milieu.

(though I also made a bootable cd flash in case something happens)

1 person liked this | cliffordcooley cliffordcooley, TechSpot Paladin, said:

though I also made a bootable cd flash in case something happens
Thats just it, if something happens your system will be bricked and the CD will do no good. Thats why they started placing BIOS backup solutions on motherboards with the push of a button.

Wagan8r Wagan8r said:

What's missing from this story is that if you overclock your PC from the BIOS, the benchmark results are completely accurate. Only by adjusting the clockspeed within the OS produces the skewed results.

misor misor said:

What's missing from this story is that if you overclock your PC from the BIOS, the benchmark results are completely accurate. Only by adjusting the clockspeed within the OS produces the skewed results.

how did you know that?

Thats just it, if something happens your system will be bricked and the CD will do no good. Thats why they started placing BIOS backup solutions on motherboards with the push of a button.

thanks for the caution, I thought bios flashing by any means provided by the mobo vendor are equally safe (relatively).

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