Aluminium Macbook: Underclocked in bootcamp??

Discussion in 'MacBook' started by darienphoenix, Nov 17, 2008.

  1. darienphoenix macrumors member

    Nov 12, 2008

    I recently bought a 2.4GHz Aluminium enclosure Macbook, and love it to bits.

    However, when running Windows XP Pro under Bootcamp, it seems like the CPU is underclocked. Both CPUz and CoreTemp report the CPU clock frequency as 1.6GHz, rather than the 2.4GHz it should be (multiplier at 6x, and FSB at 265 Hz).

    Is this a design decision? If so, why? If not, can I get into EFI to fix the speeds?

    Cheers in advance if anyone can help.
  2. Skeletal-dæmon macrumors 6502

    Apr 27, 2008
    The AlBooks at work don't seem to have this problem, with the exception of one which also lists only RAM in DIMM0... the tech guys are on it but haven't the foggiest why Windows is being so strange about it - when in OS X the machine is perfectly happy to denote its 2.4GHz and all 4GB RAM.

    The favorite theory of the most zealous of the tech guys is that "Windows is stupid." - he got a few laughs.

    (A point to remember if you read this and decide to check your RAM too... XP Home and I think its Pro SP 2 limit the RAM to 3.somethingGB)
  3. darienphoenix thread starter macrumors member

    Nov 12, 2008
    It's listed as 1.7 GB of ram in Windows, I assume because 256MB is allocated to the video card.

    Apparently I'm the only one having this problem then?
  4. No1451 macrumors 6502

    Oct 20, 2008
    Ottawa, ON
    Might be Intel SpeedStep? Happens on my desktop too, from 3.2 down to 2.1.

    And if anyone DOES say its cause Windows is stupid, well you have your answer.

    Also to answer that RAM supposition, its not Windows that makes it limited, its 32bit windows that limits your max amount of ram, the 4gb I have in my desktop is all showing up perfectly(cause its 64bit)
  5. Jollins macrumors regular


    Jun 9, 2006
    Sounds like power management to me. It improves battery life and keeps the temps down, but it will ramp up to full speed when something needs it so you shouldn't notice a performance loss. OS X does this too.
  6. dbdynsty25 macrumors regular

    Nov 9, 2008
    Thousand Oaks, CA
    Exactly. If you change your power profile in the Windows Screen Saver section to Desktop instead of goes back to 2.4ghz.
  7. Skeletal-dæmon macrumors 6502

    Apr 27, 2008
    Hmm I'll give this a go tomorrow and see how it effects the AlBook. Still not sure about the RAM, might just be an odd DIMM slot.
  8. darienphoenix thread starter macrumors member

    Nov 12, 2008
    Ah, I forgot about SpeedStep. I haven't had it turned on in a PC for years, because I overclock all my desktops, and this is the first time I've had Windows on a Macbook using Bootcamp rather than a VM.

    Thanks for the help, I'll load the CPU next time and check if it goes back up to 2.4GHz.
  9. reeveah macrumors member

    Oct 23, 2008


    I've bootcamp the 2.4ghz MB alu running 4ghz but the processor only reflects 1.58ghz.

    How do i rectify this problem then?
  10. peskaa macrumors 68020


    Mar 13, 2008
    London, UK
    Try reading the topic?
  11. aznguyen316 macrumors 68020


    Oct 1, 2008
    Tampa, FL

    but yeah change the power setting of your OS. I didn't check mine before I changed it, but intalled nvidia system tools and mine shows correct clock. I also OC'ed mine in bootcamp though to 299FSB I forget the multiplier (7.5?) to ~2.3Ghz and stays cool thanks to SMC fan on the OS X side. And OC'ed the GPU a bit too. Just for gaming.

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