Hyperthreaded processor/no way to turn it off

Discussion in 'OT Technology' started by patio87, Feb 20, 2007.

  1. patio87

    patio87 New Member

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    So I just installed a P4 2.8Ghz HT processor on my pc, and I want to turn HT off. I went into my BIOS setup and there is no where that I can do it, am I stuck with HT on?

    One other thing, whenever I do a processor speed test(i've done 2 know) it's still coming up as 1.4Ghz which was my last cpu, eventhough when I go into windows task manager in the CPU Usage History, it show up as 2 processors, as you'd expect with a HT processor.
     
    Last edited: Feb 20, 2007
  2. SLED

    SLED build an idiot proof device and someone else will

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    Why would you want to turn HT off :dunno:

    Are you using the same motherboard as your last setup? What does the bios report the cpu speed as?
     
  3. crontab

    crontab (uid = 0)

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    are there any bios updates that include the toggling of HT?

    does the bios report the speed as well?

    did you change the multiplier and fsb when you put in the new cpu? if you still need to do that...
     
  4. 5Gen_Prelude

    5Gen_Prelude There might not be an "I" in the word "Team", but

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    If you leave off the chipset drivers, it won't run in HT mode. Probably not what you want but I thought I'd throw it out there anyway.
     
  5. deusexaethera

    deusexaethera OT Supporter

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    Why would you want to disable Hyperthreading? It allows the CPU to store two assignments at once, so if it has to stop running one program (maybe because that program is waiting for data from the hard drive) it can just start running the second program without having to ask Windows what to do next. It's much more efficient -- and it doesn't actually split your CPU in half, like it appears in Task Manager.
     
  6. crontab

    crontab (uid = 0)

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    Back when we had a bunch of machines with HT, we disabled it on a number of them because it degraded performance. A big flaw with HT is that it uses the same cache for both threads. This can cause a form of double buffering and unwanted crap in the cache, which will fill it up sooner than later and increase latency. Since there are no API's for HT for ISV's to tag onto, they couldn't truly control what gets cached and what doesn't. Solution? Turn it off. The boxes most affected are ones that are in a OLTP and OLAP environment. Batch processing, not so much.

    There was a security hole with HT and RSA keys in 04 and 05. But these have been patched in the OS. Also due to the shared cache "feature".

    Why one would want to turn it off for home now, no idea.
     
  7. deusexaethera

    deusexaethera OT Supporter

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    Yeah, I guess in a situation where you're running a number of heavy processes that load up the cache with data that will have to get reloaded each time the Hyperthreader does its thing, it could be a problem. But like you said, for home use shutting it off isn't going to improve performance by any measurable amount.
     
  8. P07r0457

    P07r0457 New Member

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    turning it off will hurt some things, and help others.
     
  9. patio87

    patio87 New Member

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    The reason I want to turn it off is for gaming, almost all of the benchmarks I have read say that HT off for gaming will give you increased performance.

    " did you change the multiplier and fsb when you put in the new cpu? if you still need to do that..."

    How do I do that crontab?
     
  10. deusexaethera

    deusexaethera OT Supporter

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    There should be a setting in the BIOS to disable it; failing that, I think Intel makes an application that allows access to BIOS settings from within Windows.


    Anyway, make sure to run those benchmarks yourself if you manage to find a way to disable Hyperthreading; HT has been around long enough now that either Windows or some of your games might have some kind of optimization
    that makes the old HT-disable trick obsolete.
     
  11. P07r0457

    P07r0457 New Member

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    THE OMGZ I REEDS IT ON DAZ INTANETZ AND DIS MUST BE TRU!
     
  12. patio87

    patio87 New Member

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    jollyogre = Ignored. Good job faggot.:rofl::rofl::rofl::rofl::rofl::rofl::rofl::fawk::fawk::fawk::fawk:
     
  13. patio87

    patio87 New Member

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    Yeah that's true, Oblivion I know has settings to optimize HT in the ini files. I just don't understand why in my cpu tests it's coming up as 1.4GHz, is it just that it is reading one, and that's why it's not coming up as 2.8?
     
  14. Peyomp

    Peyomp New Member

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    Lets leave our women and elope to an Island.
     
  15. deusexaethera

    deusexaethera OT Supporter

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    It's certainly plausible, though between my family and my office I've only ever used two HT processors, and I never really bothered to check if the speed readout changes.
     
  16. crontab

    crontab (uid = 0)

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    These steps would be in your mobo manual.
     
  17. RiSk

    RiSk New Member

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    9/10 to turn off HT its in the Bios or atleast thats how it is at the server farm where i work :p
     
  18. Doc Brown

    Doc Brown Don't make me make you my hobby

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    Mistake #1.

    Jolly is an aquired taste, and some like Young Peyomp for instance
    enjoy the whole swallow thingy.

    They're young, rude, obnoxious, and they probably don't wash their dicks
    before they penetrate you, but they know their shit.
     

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