Overclock GPU under OS X

Discussion in 'iMac' started by Neryus, Apr 20, 2015.

  1. Neryus macrumors member

    Joined:
    Jun 25, 2013
    #1
    Hi guys!

    I have an iMac late 2013 with the NVIDIA 780M graphics card. As I read on multiple sources, Apple likes to underclock their GPUs in OS X, to avoid the fan beeing noisy.

    Is there a possibility to change the clock of the GPU to normal under OS X? There used to be tools like Zeus that were able to do this several years ago, but I couldn't find anything working with newer Macs and Yosemite.

    Are there tools to do this?
     
  2. The-Pro macrumors 65816

    Joined:
    Dec 2, 2010
    Location:
    Germany
    #2
    well if you have windows installed you can check what the clock speeds are actually at. Install GPUz, it will tell you the current clocks and max clocks
    I have not heard of apple underclocking the 780 in the iMac. If they did there would be a rage thread here somewhere :D
    I do not think a solution for overclocking in OSX exists at the moment :(
     
  3. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #3
    Windows Overclock

    If a graphics card is overclocked in Windows, will the overclocking work in OS X or will there be no change in performance in OS X?
     
  4. The-Pro macrumors 65816

    Joined:
    Dec 2, 2010
    Location:
    Germany
    #4
    overclocking in windows will only overclock it in windows. No difference in OSX.
     
  5. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #5
    Okay

    Oh. I was hoping that the changes would be implemented in the BIOS of the graphics card. I guess I'd have to use something like NiBiTor for that.
     
  6. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    To OC a GPU under the current OSX is not recommended. It require to flash the graphic card. That means for a computer like iMac, the process may kill the whole computer, and no easy fix.
     
  7. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #7
    Okay. By the way, the graphics card I might overclock is a desktop card, the GT 740.
     

    Attached Files:

  8. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #8
    OK then. I am not an expert for that card. However, it's possible if the card is flash-able.

    1) Go to Windows
    2) Use GPUZ to dump the BIOS
    3) Back up that ROM x2
    4) Hex edit it or use any tool that good for that particular ROM image
    5) Flash it back to the card

    Then the card is OCed in OSX. Of course, it takes lots of time to get the clock / voltage right (if you want to max it out safely).
     
  9. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #9
    Thanks

    Okay, thanks. I think I would just use NiBiTor in OS X.

    I have one more question: Would 52 megahertz count as a minor increase in clock speed?
     
  10. The-Pro macrumors 65816

    Joined:
    Dec 2, 2010
    Location:
    Germany
    #10
    Highly unlickely you will see any sort of significant improvement from a 52MHz higher clock speed.
     
  11. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #11

    Okay, thanks. I thought it would only be a minor improvement. I just thought it best to ask since I don't have any hands-on experience with graphics cards.
     
  12. VicLev macrumors member

    Joined:
    Jun 6, 2013
    #12
    have you managed to actually dump the vbios from 780m?
     
  13. jblagden macrumors 65816

    jblagden

    Joined:
    Aug 16, 2013
    #13
    780m? I think you've got the wrong guy. I don't have any laptop GPUs, let alone a 780m.
     

Share This Page