Hello, I recently bought a prebuilt CyberPower PC with an RX 580 and out of the box my Sceptre U40 4K TV is being seen as only supporting 3840 x 2160 30Hz. I can't lower the resolution to 1080p or raise the refresh rate to 60Hz without getting an "unsupported by your display error" in Radeon custom resolution settings. I'm using the HDMI 2.0 cable that came with my Xbox One S and 4K 60 works fine on that.
Necro-bump, but this is still showing up in relevant search results. I ran into similar symptoms on an RX 7900 XT with a Sceptre 4K TV. The solution on my end was discovering that the Sceptre unit, while supporting HDMI 2.0, was factory-set to use HDMI 1.2 for compatibility reasons. Navigating the TV menu and bumping the running HDMI version to 2.0 resolved my bandwidth issues, allowing use of 4K@60Hz.
