iMac 27" 5K and 144hz external monitor

[livit]

Hello guys

I love my iMac 27" 5k (late 2017). Besides work in OS X, I also boot into Windows 10 for gaming.
In FPS games, I am however missing some more hz than the default 60, as I've tried my friend's 120/144hz monitors many times, and there's a big difference.

Is it possible to hook up an external 24" 144hz monitor, and use this screen running 144hz?
I dont mind if the iMac display goes black whilst running the other, they dont necessarily have to run at the same time.

I'd just want some +60hz gaming, without investing in a Windows gaming rig.

Let me know what you think, or if you have any experience with this. To my knowledge, dual link DVI is required for a 144hz monitor to deliver the full 144hz. It's not a problem to find a USB 3 thunderbolt to DVI adaptor, just not sure if it will work as I hope?

 

[livit]

No one?

 

[Fishrrman]

Perhaps the only way to know will be to connect the display to the Mac and "see for yourself"...

 

[livit]

For future research and references, here's my experience.

I got it working. It was however with an crazy expensive adapter (99 USD) (cheaper possible alternative described later)
https://www.apple.com/shop/product/MB571LL/A/mini-displayport-to-dual-link-dvi-adapter?fnode=8b

You need to use a DVI Dual link adapter cabling solution, as at least this monitor BENQ XL2411 requires this signaling to go full 144hz.

On top of that, since it uses Mini-Displayport in, and the newest iMac has USB-C instead, you also need a USB-C to Mini-Displayport adapter. These are fairly cheap though.
In OS X as a secondary monitor - I can get it to run up to 120hz. 144hz is available as option, but when selected, the screen display grey/pink/green static, and is non-usable. 120hz seems to run fine.

After bootcamping into Windows 10, I've set the external monitor to be the only one active, to not waste any GPU capacity, powering the iMac 5K display. This way, I am able to fully utilise the potential of the external gaming monitor, going full resolution at max hz (144hz). Works great so far, in games as well.

Before buying into this expensive adapter setup, I tried a USB-C to DVI adapter, as it was simpler and much cheaper, but this didn't work out too great. I was able to push the monitor to 120 hz, but only at extremely low resolutions, so hardly usable.

I also found this adapter, which I think would work as well. This could be the ideal one to use, as it is cheaper, and simpler. Compared to the cheaper one I also tried, this is a DVI dual link, which is necessary for 144hz.
https://www.startech.com/AV/usb-c-video-adapters/usb-c-dvi-cable-1m~CDP2DVIMM1MB

 

[Elliot Boney]

Sorry to bump an old thread but I was desperately trying to find a gaming solution for my 5k imac and found your awesome tips! I was wondering if you had any updates to your rig or any new/better/cheaper solutions since your original post