When playing back 50 FPS videos (1080p or 4k doesn’t matter), the HDMI link between the X96 Max Plus and the AVR (Onkyo TX-NR575E) sometimes breaks for about a second, resulting in a black screen, and audio outage for the same time. This happens about 1 to 4 times per hour. I can see the audio channel icons disappear from the AVR display, that is how I know the issue is between the X96 and the AVR.
It doesn’t happen for 23.976 FPS video, playback is fine. I have replaced the HDMI cable with a different one, the issue remained the same.
Log didn’t show anything unusual during the dropouts, as if the X96 was not aware of the them.
We replaced the HDMI cable to a third one, and replaced the cooling on the SOC with a larger heatsink, and thinner heat conductor. The original heat conductor was 2-3 mm thick, pressed against a metal plate and the head of the screw holding the metal plate. It was ugly. You can see the factory cooling here.
It is working fine since these changes, no dropouts (black screens) on HDMI.
I can see dropped frames here and there, but it is far better than our other HTPC with an NVIDIA GT1030. The GT1030 just can’t handle 4K nicely.