IMAC Excessive Overclock

Discussion in 'iMac' started by Retromac2008, Mar 1, 2018.

  1. Retromac2008 macrumors regular


    Oct 9, 2015
    i m gaming on a old imac with gtx 680mx.

    i overclocked the gpu and i have

    - 90°c (93° max) gpu
    - 70°c (76°max )CPU
  2. iMacDonald macrumors member


    Oct 27, 2016
    Still less than some of the 7700K reports I've seen.

    I really wish there was an option to get the non clocked 7700 i7 in the 27 iMac. :(
  3. Mac32, Mar 1, 2018
    Last edited: Mar 1, 2018

    Mac32 Suspended

    Nov 20, 2010
    I did this for 5 years with 0 issues. From my experiences the perfect 680MX overclock is +250/+375 (MSI Afterburner), anymore and the temp starts to rise noticeably with no real performance gain. Also higher overclocks than this can give random reboots in dx11+ games, probably from drawing more power than the iMac PSU can handle.

    Also use Macs Fan Control for Bootcamp, and set a static fan speed like 2250-2350rpm for the most demanding games. Your GPU temperatures should stay within the 80s (Celsius). This is with the assumption that your 680MX unit behaves similar to what mine did.

    Don't forget to cap the framerate at 59 (MSI Afterburner), which reduce triple buffered vsync lag (use D3DOverrider), and avoids that the GPU works harder than it needs to (ie. avoid unnecessary GPU heat).
  4. Retromac2008 thread starter macrumors regular


    Oct 9, 2015
    wow, thank you for the report

    i m glad it s safe, but it s impossible to stay under 80° :(
    actually it s always at 90° when gaming

    my oc is exactly the same, and i had problems only with the last nvidia driver (the last 2 days) with overwatch
  5. Mac32 Suspended

    Nov 20, 2010
    No problem. :) I wish Apple would use Nvidia GPUs again. If you need a new driver, you can just go to, and get the latest official one. With AMD things are more complicated, though Apple is to blame for this. Afaik it's Apple who wants control the Bootcamp driver, which is utter nonsense.

    As far as the higher temperature, it could be down to playing newer games being more taxing on the GPU. You could always turn down the overclock a bit for those games, which I would sometimes do during hot periods in the summer months.

Share This Page

4 March 1, 2018