Overclocking MBP i5

Discussion in 'MacBook Pro' started by mark28, Jul 22, 2010.

  1. mark28 macrumors 68000

    Joined:
    Jan 29, 2010
    #1
    I was thinking of overclocking the CPU from 2.4 ghz to either 2.53 ghz or 2.66 ghz, to make it comparable in performance to the higher end models.

    I know for desktops it's very silly to buy the higher end cpu, because a little overclocking will give the exact same performance.

    Anyone knows if the same holds true for laptop CPU. ( I think the i5 2.4 ghz and 2.53 are identical except in clock speed, so a little overclock to 2.53 ghz should atleast be possible right? )

    And are there guides on how to overclock on a Mac/OS X? :)
     
  2. Hellhammer Moderator

    Hellhammer

    Staff Member

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    Finland
    #2
    Macs don't have BIOS or open EFI so you cannot overclock like you can in PCs. AFAIK, there is no way to OC under OS X. Under Windows it should be possible but that will only work at Windows, when booting into OS X, it'll be the default clock
     
  3. Str8edgepunker macrumors 6502

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    Nov 4, 2001
    Location:
    Philadelphia, PA
    #3
    Well, there was a way, it's called spending an additional $200 for 2.53ghz and $400 for 2.66. Realistically though, the 2.4 is only, maybe about 10-15% slower than the i7 2.66 so I think the real question is why?

    Besides, these laptops run hot enough...
     
  4. demonsavatar macrumors regular

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    Jun 26, 2010
    #4
    There is a utility for Mac Pro and Xserves made by the german ZDNet but it doesn't work on Macbooks/MBPs.

    I know for C2D MBPs coolbook allowed you to UNDERclock, maybe it allowed overclocking too?

    Until we find or create a utility to do this, I don't think its possible on the latest MBPs...
     
  5. Hellhammer Moderator

    Hellhammer

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    #5
    I think the CoolBook simply allowed you to change the multiplier of the CPU but all other than the Extreme CPUs have locked multiplier (it can be decreased but not increased). For example, the i5-520M has multiplier of 18 (133MHz x 18 = 2394MHz ~2.4GHz), that can be decreased to e.g. 15, giving frequency of 1995MHz but the maximum multiplier is 18. Thus it would have to be overclocked by increasing the base clock

    If the CPUs had unlocked multiplier, it would be easier but playing with base clock (133MHz) is always riskier and it affects memory and uncore as well.
     
  6. demonsavatar macrumors regular

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    Jun 26, 2010
    #6
    Yeah locked multipliers are a pain. But with i5, overclocking to 2.66Ghz from 2.4Ghz should be a joke even if its done by increasing the base clock.

    I think Coolbook let you change the voltage also.
     
  7. mark28 thread starter macrumors 68000

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    Jan 29, 2010
    #7
    Well, the i5-520m and i5-540m are the identical except how they are clocked. So I figured I'll just get a cheap i5-540m by a little overclocking and the temperatures should be acceptable still :p

    But then again, I like long battery life since it's a mobile machine, so perhaps i'll just keep it at stock speeds afterall.
     
  8. demonsavatar macrumors regular

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    Jun 26, 2010
    #8
    Yeah overclocking to 2.53Ghz would be NO problem.

    I am more interested in undervolting though to save battery.
     
  9. Hellhammer Moderator

    Hellhammer

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    #9
    The issue is that you cannot change the base clock as far as I know. Also, I don't know how the EFI would response as there are several limitations that Apple has put (e.g. no +1066MHz DDR3 in Mac Pro) so it might be reseted everytime you boot.
     
  10. demonsavatar macrumors regular

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    Jun 26, 2010
    #10
    This might be why Coolbook hasn't released a version that works with Core i5/i7 macbooks yet :(
     

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