High Sierra with AMD RX580 and Samsung 4K TV - how do you get 60hz?

[Scott1204]

I was finally able to get an AMD RX580 running under High Sierra. I get sound and 4K resolution but I can’t get 60hz refresh rate.

I had an Nvidia 1080Ti and could do it with Sierra using a Club3d Display-to-HDMI adapter, SwitchResX, and the clock patch. So I know the hardware is capable.

But in High Sierra, it’s stuck at 30hz. Tried SwitchRes, various clock patches (most of which say they don’t work on AMD), HDMI with no Club3d adapter ... can’t make it work.


Any suggestions?

 

[jerryy2345]

In reading this, it sounds like you have tried a lot of things, but getting it working will be tricky:

https://support.apple.com/en-us/HT206587

"HDMI displays
You can use 4K displays and Ultra HD TVs at the following resolutions and refresh rates via the built-in HDMI port of your Mac:
• 3840 x 2160 at 30Hz
• 4096 x 2160 at 24Hz (mirroring is not supported at this resolution)"

if macOS decides you are connected to HDMI, it will force 30hz refresh rates on your monitor -- this has been an on-going and off-going issue for some time.

Can you find a DisplayPort to HDMI adaptor that does not 'fess up that it is passing the signal to HDMI equipment? Or find a 4K monitor that lets you connect via DisplayPort? That approach will let you use 60hz.

 

[Scott1204]

Thanks, I do have a DisplayPort adapter that fixes the issue for Nvidia running Sierra...just not seeing a similar patch for AMD

I had to switch back to my Nvidia 1080Ti. Was trying to keep both cards in one machine and realized my motherboard can’t boot from the righ PCI slot to make the combo work

 

[TomHsiung]

I heard that now HDMI@60Hz is supported.