I'm trying to run Linux at the full 165Hz refresh rate supported by my monitor, but anything above 120Hz causes flickering and other display problems. My graphics card is an AMD RX 6600, and I've reproduced the issue on Linux Mint, CachyOS, and Bazzite. The monitor is 1080p and currently connected over HDMI. What should I check to get 165Hz working reliably?
3 Answers
First, try DisplayPort instead of HDMI. High refresh rates can be unreliable over HDMI depending on the monitor, cable, and GPU connection, while DisplayPort is generally the better choice for 165Hz. Also make sure the cable is properly seated and rated for the required bandwidth.
Check whether the problem happens in both X11 and Wayland sessions. Those are different Linux display systems, and some hardware or driver issues only appear in one of them. Your desktop environment’s session-selection menu usually lets you choose between them when logging in.
It may also be worth reseating the display cable at both ends and rebooting afterward. A loose or marginal connection can work at 60 or 120Hz but start failing when the bandwidth increases. If DisplayPort still flickers, try another known-good cable and confirm that the monitor’s on-screen settings allow 165Hz.

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