4K@60Hz Display Artifacting on Cubie A5E - Need Help

[Akhil]

Hi,

I am experiencing severe display artifacting on my Radxa Cubie A5E when using a 4k@60Hz display, specifically during memory-intensive tasks (membench, Chrome, window dragging).

• Board: Radxa Cubie A5E
• OS: a527_cubie_a5e_bullseye_beta_20250303_raw_disk image https://linux-sunxi.org/Radxa_Cubie_A5E
• Connection: HDMI 2.1
• Video: artifacting video

What I’ve Tried:

• Multiple HDMI 2.1 cables.
• Different GPU drivers.

Observation:

• Issue only occurs at resolutions above 4k@30Hz like 4k@50Hz. No artifacting at 1080p or 4k@30Hz.

Is anyone else seeing this problem with this board/image? Can anyone replicate it or suggest a fix so that I can rule out hardware issues?

Thanks!

[Akhil]

Further testing reveals that I can achieve a somewhat stable 50Hz at 4K by changing the color space to YCbCr410 or YCbCr420. Even BT2020NC shows some improvement. Applying xrandr --output HDMI-1 --mode 3840x2160 --rate 50 --set color_space BT2020NC provides this result. (4k@60 YCbCr420 should be possible even with HDMI 1.4 bandwidth but I was not able to)

Trying alternative OS images from the wiki and Android (which was stuck at 720p), did not fix the artifacting.