4k60hz on 2012 iMac

[TechInit]

Hey everyone,

I just bought a Samsung UR55 monitor, and I never actually checked if my iMac could run it (stupid, I know). To my knowledge, the GTX 680MX supports DisplayPort 1.2, which can do 4k60hz, but the GK104 chip is limited to 3/4 of the true transfer speed of DP 1.2 (which can still do 4k60hz). I know that the 680MX uses that chip, but I'm not 100% sure if the same laws apply to this specific variant, or if its had even more things altered with it, because the GTX 680M uses the GK104, but it can only output up to 2560x1600.

Many thanks,
Leo

 

[Nguyen Duc Hieu]

You have already had both the iMac and the monitor.
Now you just need a miniDisplayPort to DisplayPort cable to verify your question.
Be confident my friend.
We are looking forward to a successful report here.

 

[TechInit]

Just by using a cable I had laying around, it appears to only do 4k30Hz. I'm going to buy another cable which is advertised for HBR2, just to be completely sure that its not the cable, because I've read that some DisplayPort Cables can't transfer the bandwidth required for HBR2. Not too fussed however as I can use this monitor when I get my next computer, and for £200, I'm not complaining. I can also run it at 2k60, so that might just have to do for the time being.

I'll update the thread once I have a new cable

 

[TechInit]

After testing with 2 cables, I can definitively say that you cannot run a 4k60 Display from the 2012 iMac, despite the GTX 680 supporting HBR2 transfer speeds. This could mean that the chip in the 680MX and 680 are somewhat different, despite the general consensus online. If you don't mind the mess that is 30Hz, then it does work, but for an overall good experience, the GTX 680MX simply cannot do 4k60. Despite this, 1440p still looks great on a wide range of monitors, so if you're waiting for the new M1 iMacs, but want to get your 2nd or 3rd display now, it works totally fine, as long as you are fine waiting before you can use your monitor to its full potential.