What are the disadvantages of turning off hyper-threading?

Discussion in 'CPUs and Overclocking' started by avi85, Oct 25, 2006.

  1. avi85

    avi85 Senior member

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    I was wondering what the disadvantages of turning off hyper-threading are (I saw the option in the BIOS)? Are there any advantages? this is in a 3.0GHz Prescott socket 478.
     
  2. BrownTown

    BrownTown Diamond Member

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    Disadvantages would be lower multithread performance in some apps. Advantges would be slightly better performance in some apps. Its mostly just a cr@pshoot whether or not it will help what you are doing, so unless you have a specific program in mind it doesn't I would just leave it on.
     
  3. imported_goku

    imported_goku Diamond Member

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    Just keep it enabled, it will prevent one buggy application from taking all the CPU cycles away from the system. It definately has a performance improvement when an application is coded to take advantage of it. The difference between HT and non HT is like the difference between a P4 3.5GHZ HT off and a P4 3.8GHz HT off. (300mhz difference)
     
  4. stevty2889

    stevty2889 Diamond Member

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    Hyperthreading genraly gives about a 15-20% performance increase in SMP aware programs, and helps with multi-tasking. Other than a few games, games are not SMP aware, and don't see a benifit from hyperthreading, unless you have some CPU intensive programs running in the background. There are also some odd programs here and there that perform better with HT turned off, but not usualy by a large amount.
     
  5. RussianSensation

    RussianSensation Elite Member

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    3.06 w/HT outperforms 3.6ghz w/o HT

    Watch THG Video 5
     
  6. BrownTown

    BrownTown Diamond Member

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    ^actuall results may vary^
     
  7. StrangerGuy

    StrangerGuy Diamond Member

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    More sluggish multitasking and SMP-programs runs slower. There is zero reason to turn HT off anyway; it is easily the best feature of the netburst architecture.
     
  8. secretanchitman

    secretanchitman Diamond Member

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    slower SMP performance, but not by much. i'd just leave it on (you go from a 533FSB to a 800FSB).
     
  9. stevty2889

    stevty2889 Diamond Member

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    ??? Hyperthreading has nothing to do with the front side bus..
     
  10. imported_goku

    imported_goku Diamond Member

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    Hmm, well while that IS an interesting video, what needs to be compared though is single application, multithreaded performance.

    I came up with the 300mhz figure because I overclocked my processor to 3.8ghz one time and disabled HT, ran sisoft sandra then I compared the scores of my 3.5GHZ overclock with HT on and the scores were about the same.
     
  11. Auric

    Auric Diamond Member

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    Disabling HT would be like having a Celeron or Athlon XP... completely neutering multitasking and video performance. Well, Athlon XP still couldn't compete due to lack of SSE2 +.