Another look at HPET High Precision Event Timer

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

  1. Bukkake

    Bukkake Active Member

    Messages:
    83
    Likes Received:
    0
    GPU:
    EVGA SC GTX 780Ti OC
    I came across this site

    http://www.neowin.net/forum/topic/1...n-bios-and-os-for-better-performance-and-fps/

    i used to have hpet disabled in bios and it was also disabled in my windows.

    now i enabled it in the bios and i enabled it in windows.

    i have yet to test any games and i dont really notice any difference

    my max latency in dpc latenacy check is 132 us

    in the topic there is wildy different results

    but with my computer in non gaming related usage i dont see any differnce at all.
     
  2. HonoredShadow

    HonoredShadow Ancient Guru

    Messages:
    4,220
    Likes Received:
    1
    GPU:
    MSI 980Ti OC+ASUS Swift
    How do you test if its enabled in windows?
     
  3. Prophet

    Prophet Master Guru

    Messages:
    778
    Likes Received:
    0
    GPU:
    Msi 680 Gtx Twin Frozr
    You can only set it in bios. You cannot enable/disable it from windows either. Asus bioses tend to have it, other vendors you have a to have a bit of luck. I think more and more are implementing it in bios updates.

    Edit: You can enable/disable hpet from the devmanager but that doesnt enable/disable it.

    Edit 2. :(
     
    Last edited: Sep 18, 2012
  4. IcE

    IcE Don Snow Staff Member

    Messages:
    10,654
    Likes Received:
    11
    GPU:
    Gigabyte 970 G1
    You assume it's on unless you've turned it off in the BIOS.
     

  5. WhiteLightning

    WhiteLightning Don Illuminati Staff Member

    Messages:
    26,662
    Likes Received:
    30
    GPU:
    Inno3d GTX 1070 iChill x4
    You need WinTimerTester 1.1 to test it. its off by default (even for windows 8).
    (so setting in the bios alone does nothing, has to be enabled in windows aswell).
     
  6. HonoredShadow

    HonoredShadow Ancient Guru

    Messages:
    4,220
    Likes Received:
    1
    GPU:
    MSI 980Ti OC+ASUS Swift
    Really? Oh! It is on by default on my PC but its not doing anything then?

    Is it best on or off in bios and windows?
     
  7. WhiteLightning

    WhiteLightning Don Illuminati Staff Member

    Messages:
    26,662
    Likes Received:
    30
    GPU:
    Inno3d GTX 1070 iChill x4
    i really dont know. there are positive and negative reports. best is to see for yourself.
    i wanted to use dpclatency checker , but since im on windows 8 its not supported as of yet. giving the wrong values :(
     
  8. HonoredShadow

    HonoredShadow Ancient Guru

    Messages:
    4,220
    Likes Received:
    1
    GPU:
    MSI 980Ti OC+ASUS Swift
    Well I did try with it off in the past and what i saw happen with DPC Latency tester was that my overall latency (idle) was done consistently but when I did do something like load a game or open firefox etc. then I noticed the latency spiked higher than before by quiet a bit.

    This was all of course without me knowing that I had to enable it in Windows (which I have no clue how too!)

    I'm sure I already had a thread on this.
     
    Last edited: Sep 18, 2012
  9. HonoredShadow

    HonoredShadow Ancient Guru

    Messages:
    4,220
    Likes Received:
    1
    GPU:
    MSI 980Ti OC+ASUS Swift
    Last edited: Sep 18, 2012
  10. Noisiv

    Noisiv Ancient Guru

    Messages:
    5,827
    Likes Received:
    3
    GPU:
    R9 290 ACIV 1150/1500MHz
    Snake oil :)
     

  11. -Tj-

    -Tj- Ancient Guru

    Messages:
    13,861
    Likes Received:
    7
    GPU:
    ZOTAC GX980Ti Amp!Extreme
    If its running at 14.31818MHz then its enabled.


    And to use this 14.3mhz as the only clock open CMD (run as administrator) and type in bcdedit /set useplatformclock true


    I use this option since Vista days and it never caused any issues at 90-150us, actually it helped with X-FI drivers, if i used 2MHz (HPET off) i got some 250-350us spikes time to time. :)
     
  12. PhazeDelta1

    PhazeDelta1 Moderator Staff Member

    Messages:
    15,613
    Likes Received:
    1
    GPU:
    EVGA 1080 FTW

    More like Placebo. :nerd:
     
  13. kalston

    kalston New Member

    Messages:
    9
    Likes Received:
    0
    GPU:
    Gigabyte GTX 670
    Not exactly placebo.

    When I enable it in windows and get 14.3 or so mhz in wintimertester my system feels completely different. It is smoother but everything is somewhat slower and delayed. The difference is very noticeable for me (and some other people have reported the same thing on neowin forums).

    And regardless of the windows configuration enabling it or not in the bios makes a slight difference in terms of DPC latency (apparently windows uses different timers by default so disabling HPET in the bios means one less conflicting timer to use and lower DPC latency). However apart from the DPC latency readings I certainly can't tell the difference in benchmarks or games between HPET ON/OFF in the bios. It's only by enabling it in both windows and the bios that I notice a BIG (and NEGATIVE) difference. Why don't you just try it for yourself? It's harmless and easy to revert the changes.
     
    Last edited: Sep 18, 2012
  14. TheDeeGee

    TheDeeGee Ancient Guru

    Messages:
    5,098
    Likes Received:
    4
    GPU:
    MSI GTX 1070 AERO OC
    Running at 14.31818 MHz for me.

    I enabled it not long ago. Set it to 64-Bit in BIOS and enabled it in Windows with the Command shown earlier.

    Ever since i enabled it everything ingame does feel somewhat smoother.
     
  15. Mineria

    Mineria Ancient Guru

    Messages:
    3,780
    Likes Received:
    4
    GPU:
    Asus Strix GTX 1080
    From CMD: bcdedit /enum
    One line should say: useplatformclock Yes

    Althoug it seems to be more related to FSB overclocking.

    Ive seen a few mention that it fixes multimedia playback issues, and even IBM advices that it gets via bcdedit enabled for certain software/hardware combinations.

    EDIT: Something for Windows 8 users:
    bcdedit /set disabledynamictick yes
    What it will do is stop Windows from coalescing CPU clock ticks when idle, a feature added in Windows 8 for power savings.

    If you have real high DPC spikes your better of investigating which driver or software that causes it thou, since neither of the 2 settings above will help upon that.
     
    Last edited: Sep 18, 2012

  16. Mineria

    Mineria Ancient Guru

    Messages:
    3,780
    Likes Received:
    4
    GPU:
    Asus Strix GTX 1080
    What kind of motherboard are you using?
    You should also check the output with this tool: http://www.resplendence.com/latencymon or with xperf: http://social.technet.microsoft.com...l/thread/aa16c25a-9c72-4579-ba02-cea920296271
     
  17. Prophet

    Prophet Master Guru

    Messages:
    778
    Likes Received:
    0
    GPU:
    Msi 680 Gtx Twin Frozr
    http://www.sevenforums.com/general-...cdedit-set-useplatformclock-true-command.html


    bcdedit /set useplatformclock true (then reboot) is said to enable HPET using Win 7.

    bcdedit /deletevalue useplatformclock (then reboot) is said to remove it.

    So full credit goes to the guy on sevenforums.
     
  18. Mineria

    Mineria Ancient Guru

    Messages:
    3,780
    Likes Received:
    4
    GPU:
    Asus Strix GTX 1080
    It will not enable it if it is disabled in your BIOS.
    Quest was: How do you check if it is enabled on Windows, btw. ;)
    Where the command is: bcdedit /enum
     
    Last edited: Sep 18, 2012
  19. brendanvista

    brendanvista Master Guru

    Messages:
    237
    Likes Received:
    0
    GPU:
    GTX 980 Ti
  20. Mufflore

    Mufflore Ancient Guru

    Messages:
    10,329
    Likes Received:
    54
    GPU:
    1080ti @2GHz air
    I tried this last night and it made very little difference for me, but I didnt have any issues with jerkiness or perfomance before this.
    Before doing it, wintimertester reported my QueryperformanceFrequency as 3MHz, after it was 14MHz (to clarify that HPET is fully active and is the sole event timer).
    I did a few benchmarks prior and afterwards, namely Heaven 2.5, Heaven 3.0 (both GPU limited), Crysis Warhead DX10 (GPU limited) and X3:TC benchmark (CPU limited).

    Results:
    All results were identical (within 1%) except X3:TC which dropped from 141fps to 131fps (7% drop).

    Further observations:
    During the loading of Crysis warhead, the grey loading map showed more frames on screen.
    There is a lot more EM noise on my microphone socket on my Auzentech Prelude soundcard (used for listening to satellite TV through PC as I'm not using a pre-amp or audio switch), while running the benchmarks.

    I dont doubt that some people will find it helps in an extreme circumstance, but not for me.
    In fact it caused slightly lower framerate in the CPU limited test, although being CPU limited is not common with todays games.
    I'll keep my eye on this.

    If I dont see any further issues, I wont change back.
     

Share This Page