Another look at HPET High Precision Event Timer

Discussion in 'Videocards - NVIDIA GeForce Drivers Section' started by Bukkake, Sep 18, 2012.

  1. mbk1969

    mbk1969 Ancient Guru

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    So disable HPET in BIOS.

    Edit: In case your rig needs HPET disable platform clock usage by "bcdedit /set useplatformclock false". In case you have executed earlier "bcdedit /set useplatformclock true" you can try first "bcdedit /deletevalue useplatformclock".
     
    Last edited: Sep 10, 2013
  2. Francko1979

    Francko1979 Member

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    Thank you Sir. I´ll give it a shot and post back my findings.


     
  3. X7007

    X7007 Maha Guru

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    What does this sentence says ?

    When OS does not support HPET then it's from the bios.

    It means to disable it for OS that support it or not ? there are 2 meanings here, I want to believe to disable it from bios, because you can enable it from the OS (/set useplatformclock true).
    And people said they have better performance using it only from OS maybe because the OS uses the CPU instead of the Motherboard chip which makes it slow and high DPC because it passes through the memory chip instead directly to CPU.

    HPET Support
    Common Options : Enabled, Disabled
    Quick Review
    The HPET, short for High Precision Event Timer, is a new system timer developed by Intel and Microsoft to replace the four system timers currently in use.
    Because of its higher precision and performance, it is naturally desirable to use the HPET instead of the older system timers. However, older operating systems do not support HPET. This is where the HPET Support BIOS option comes in.

    Setting it to Enabled allows the operating system and applications to use the High Precision Event Timer (HPET) for higher precision and better performance.

    For a 64 bit operating system set it to 64.

    http://forums.evga.com/tm.aspx?m=164392


    It's like the ehci hand off setting u disable it for OS that support it, VISTA,7 I don't remember if XP does support it but I think it does.

    It's like for compability and it can cause problems if you enable it for something who has it already cause it just doing workaround for the worse.
     
    Last edited: Oct 11, 2013
  4. mbk1969

    mbk1969 Ancient Guru

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    HPET is a chip on the motherboard. If it is disabled in BIOS no way for OS to use it in any way. If it is enabled in BIOS then OS can use it.
     

  5. X7007

    X7007 Maha Guru

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    Well,, this is what I have to say about this subject,, Debugging Only is not something good to use for normal usage.

    source : http://msdn.microsoft.com/en-us/library/windows/hardware/ff542202(v=vs.85).aspx

    disabledynamictick [ yes | no ]
    Enables and disables dynamic timer tick feature. The option is available starting with Windows 8 and Windows Server 2012.

    Note This option should only be used for debugging.


    useplatformclock [ yes | no ]
    Forces the use of the platform clock as the system's performance counter.

    Note This option should only be used for debugging.

    useplatformtick [ yes | no ]
    Forces the clock to be backed by a platform source, no synthetic timers are allowed. The option is available starting in Windows 8 and Windows Server 2012.

    Note This option should only be used for debugging.
     
  6. elpsychodiablo

    elpsychodiablo Master Guru

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    Fail screenshots, 0:07 sec 0:03 sec...
    let it run at last one hour, play games in that time surf, youtube, copy some files and then compare
     
  7. X7007

    X7007 Maha Guru

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    Last edited: Oct 20, 2013
  8. Carfax

    Carfax Ancient Guru

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    I tested having HPET turned on in Windows, and my games ran noticeably worse. There was stuttering and pauses. I've heard that HPET doesn't perform well in SLI systems, so maybe that's it.

    I'm now back to using the default for Windows 8, which is invariant TSC and HPET turned on in BIOS for any program that needs it specifically.
     
  9. BenYeeHua

    BenYeeHua Ancient Guru

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    That normal for windows 8, as windows 8 start using invariant TSC more than windows 7, I think this is why I found some performance improve than windows 7, like the browser has a shorter GC time.
     
  10. mbk1969

    mbk1969 Ancient Guru

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    I believe Invariant TSC guarantees the same RDTSC readings across the cores (regardless of P-states, C-states).

    Will that thread ever go to history?... (Should I say "become a history"?)
     
    Last edited: Oct 20, 2013

  11. Pill Monster

    Pill Monster Banned

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    lol 2002.:3eyes:

    that's the oldest article I've seen on msdn...
     
  12. Dymblos

    Dymblos Member

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    I Have HPET enable by default in the bios

    but how you can enable this in Windows 8.1 ?

    Run > cmd
    then write bcdedit /set useplatformclock true
    [enter]
    then i get a denied (bcd) permission

    o_O
     
  13. HeavyHemi

    HeavyHemi Ancient Guru

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    Are you running an administrative command prompt?
    win key + x select Command Prompt (admin)
     
  14. Dymblos

    Dymblos Member

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    nop
    just the same step in windows 7.. but in 8.1 i get denied xD
    in both windows the user account have admin lvl

    ill try that tomorrow
     
  15. zedundead

    zedundead Member

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    Have you disabled UAC in Group policy? If you haven't that's most likely the reason.
     

  16. Prophet

    Prophet Master Guru

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    ie secpol.msc > local policies and something like disable local admin check
     
  17. Vbs

    Vbs Master Guru

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    Having HPET enabled in windows and having it forced as the platform clock are two very different things. You don't need to do anything to have it enabled in windows if it's enabled in the BIOS.

    What that command does is tell windows "hey, I know what I'm doing better than you, so I want to force HPET as the platform clock (for QueryPerformanceCounter)".

    Read this: http://performancebydesign.blogspot.pt/2012/03/high-resolution-clocks-and-timers-for.html :)
     
    Last edited: Oct 23, 2013
  18. tsunami231

    tsunami231 Ancient Guru

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    I still say this topic need to be sticked or remade with all the need to know info on the first Post, including the Programs need to test for latency and everything else. This topic just keep growing in time this might turn into the new Pagefile debate thread
     
  19. Reacon

    Reacon New Member

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    Hello.

    I'm trying to work something out here, since I get **** for FPS in Arma 3. After tweaking with it to a point of rage and seeing others with similar hardware have no troubles running it, I came to the conclusion that it might be something to do with the way my processor was running.

    Then I remembered I enabled HPET once upon a time, and discovered this thread, which has since consumed about 4 hours of my life.


    The Info:

    -My CPU is a Q8200 Penryn running at 400 mhz (x7) to make 2.8 GHz undervolted slightly. It is completely stable, proven reliable for the past five years of owning this PC.

    -Core Parking is OFF, all C-states disabled, EIST disabled, anything that potentially can cause instability is off.

    -HPET is enabled in BIOS, 64 bit, and - at the time of writing - enabled in Windows. I get ~14 mhz in WinTimerTester.

    -SetTimerResolutionService is running.


    The oddities:

    -dpclat.exe in HPET mode (BIOS=ON - Windows=ON) reports higher than the TSC+HPET hybrid (BIOS=ON - Windows=OFF). 170 ns vs 40ns averages respectively. There are virtually unanimous reports of latency reduction when using HPET only, despite other drawbacks.

    -My latency spikes every minute or so. This is NDIS.sys - my wifi card is screwy and I have to deal with it.

    -Stopping SetTimerResolutionService in HPET mode increases latency from 170 to 600 stable. This did not happen before I started messing with stuff.

    -WinTimerTester takes about ten minutes to settle onto 1:1 crawling upwards from .9997 in HPET mode. I was told this would take between 40 and 100 seconds.

    -I get tonnes of hard faults according to Latencymon. On occasion I will use a DAW and CPU intensive VSTs, and I experience no such audio pops or clicks from ASIO4ALL. I have a Xonar DG.

    -I've never experienced mouse lag, mouse trails, microstutters, or any other common symptoms of something screwing up.

    -My FPS in ArmA 3 jumped 20% somewhere between turning off core parking, enabling SetTimerResolutionService and putting Windows back in TSC+HPET.



    I'm clearly not very studied in this field quite yet, and I do not have a full understanding of why these oddities occur. It is also the reason why I present this post to you today, denizens of Guru3d.
     
    Last edited: Nov 7, 2013
  20. mbk1969

    mbk1969 Ancient Guru

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    Ignore these.
     

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