i7-3630qm throttles to 1200 Mhz at less then 70°C if Turbo Boost is enabled

Discussion in 'PC Hardware' started by chriz74, Oct 20, 2016.

  1. chriz74

    chriz74 MDL Novice

    Nov 1, 2009
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    #21 chriz74, Oct 20, 2016
    Last edited: Oct 20, 2016
    (OP)
    The Bios has Intel CPU microcode for the i7 in question if not it would not see the CPU at all. Once it sees it works per its specs. If it has turbo boost it will enable it.
     
  2. chriz74

    chriz74 MDL Novice

    Nov 1, 2009
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    So maybe finding where the bios sets MSR register 0x1FC to prochot enable and modify it to prochot disable. It's a bit from 0x14005f to 0x14005e but god knows where it does it. Also I found out that if I disable prochot (with throttlestop) in windows the CPU will run without any hassle while if I disable it in OSX (which is my main OS) Turbo Boost will not work even if the MSR 0x1A0 register (Turbo Boost) remains untouched...
     
  3. Michaela Joy

    Michaela Joy MDL Crazy Lady

    Jul 26, 2012
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    If that's the only register you need to set, then yeah. It'd be worth a try to experiment with it.

    If you had a ICE, you'd be able to set a trap on that location. Then, you'd know where it came from.

    There's two pieces to this:

    for one thing, you need to see what OS calls throttlestop makes. Is it Open-Source? Grab the source and take a look.

    Then you can try to examine what goes on in the OS to see what differences exist in Windows vs OSX.

    The common point is the call into the BIOS to set the registers. ;)

    Then, you need to RE the ROM image using IDA, and find that routine. You then need to analyze it to see what it's doing. Then, make the necessary changes, and flash the MoBo.

    That's a -LOT- of work.
     
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  4. chriz74

    chriz74 MDL Novice

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  5. Michaela Joy

    Michaela Joy MDL Crazy Lady

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    Could be. :)

    But I'd need to see the circuit first. Yup. Mosfets make great switches. (low Rds-on) ;)

    So ya' fixed it. :thumbsup:

    I'm glad, and I hope we've helped in some way. :)

    Best,
     
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  6. chriz74

    chriz74 MDL Novice

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  7. chriz74

    chriz74 MDL Novice

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    Looking better at the behavior with bd prochot enabled it seems the signal fires once the TDP goes over 35W. Probably i7-3612QM and i7-3632QM which both have a TDP of 35W would run without throttling too.