Discussion in 'iMac' started by Silvereel, Jun 25, 2013.

  1. Silvereel macrumors 6502

    Jan 19, 2010
    I love my 2012 iMac - it's beautiful, performs great, and does everything I need. Still, I'm intrigued by the results I've read about from overclocking the GPU, and I'm just curious how one would go about doing that. I'm pretty tech savy, but I have no experience whatsoever in overclocking. I understand the concept and what it does, but not the methodology.

    So what I'm wondering is, is it worth overclocking the 680MX on the new iMacs? How great are the results, how hard is it to pull off, and is it going to turn my beautiful machine into a brick? I have no problem monitoring temperatures now and then, but obviously I don't want to have to think too much about it when I'm just trying to enjoy a game.

    So, could someone with some experience in these things give me a few pointers? Thanks!
  2. Bear macrumors G3

    Jul 23, 2002
    Sol III - Terra
    According to what I've seen in other threads here on the forum, overclocking the 680MX is not possible.
  3. throAU macrumors 603


    Feb 13, 2012
    Perth, Western Australia
    Leave it alone.

    As soon as you over clock a chip beyond its rated spec, every single crash you have, any data corruption you have, any hang, lockup or performance glitch you have is difficult to pin down. It could be due to the over clock.

    I've over clocked in the past, back when you could take say, a Celeron 300A to 450 mhz and get a massive jump in performance for basically free.

    These days it just is not worth it. You will NOT get anywhere near 50% performance improvement (like that over clock above) and there's always the reliability in question.
  4. Chippy99 macrumors 6502a

    Apr 28, 2012
    I don't know where you've read that but it's nonsense. The 680MX in the iMac is MASSIVELY overclockable.
  5. Silvereel thread starter macrumors 6502

    Jan 19, 2010
    Mind giving some details then? I understand that there could be stability issues, but I'm confident that I could probably handle it if that were the case, and reverse things if worse came to worse. If the gains were good enough (and you suggest they are), though, I would definitely be willing to give it a shot. :eek:
  6. Chippy99, Jun 26, 2013
    Last edited: Jun 26, 2013

    Chippy99 macrumors 6502a

    Apr 28, 2012
    Well assuming you want to overclock to run games, that probably means Windows games right? If so there are a load of overclocking tools. MSI Afterburner is one of the more popular ones. There's loads of guides and youtubes and stuff showing what to do.

    You can download it here:


    You should be able to overclock the core speed quite significantly without any difficulty. Go easy and try little by little and watch the temperatures and be careful and you are very unlikely to do any harm. BUT IT IS AT YOUR OWN RISK!

  7. Silvereel thread starter macrumors 6502

    Jan 19, 2010
    I'm interested in Windows and OS X games - I use both regularly. I had rather game on OS X, but I know that Windows offers a better gaming experience in some respects, and has a larger library. That 'better experience' ends as soon as you exit a full screen game, by the way ;)

    So, for curiosity's sake, is there anything similar for OS X, or is this pretty much a Windows only affair? And if I were to apply it to Windows, any possible stability issues wouldn't affect OS X, would they? At least, so long as they are not hardware related.
  8. Chippy99 macrumors 6502a

    Apr 28, 2012
    None of the overclock settings you apply in Windows survive a reboot into OS X. So when back you OS X, you are back to vanilla and provided you haven't broken anything by being stupid in Windows land* all will be well.

    Regards OS X overclocking, it's certainly possible and various people have had a go at it, but it's much more difficult because of the lack of availability of something like MSI's Afterburner. You should do some googling ;-)

    * Note: Providing you don't mess with voltages or try to reflash a bios or anything like that, it is actually quite difficult to do permanent damage by overclocking. 99.9% of the time if you mess up, the machine will just crash or lockup and a reset brings it back. Over the years I have made some crazy mistakes and still survived. Nevertheless, be careful and take it steady. Don't whack huge overclocks in straight off and hope for the best. Start with a small incremental increase and then do some tests, check it's stable, check the temperatures. If all is well, up it a little more and repeat. At the first sign of any issues, back the speed down and test again. Having found a safe speed - where there are no issues and the temperatures are close to what you would get non-overclocked - you may wish to back it down a bit from there as well, just to be uber-safe.

    Is all this worth it? Perhaps not to be honest. But it is interesting and fun to some.

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