My X96 Max running CE last nightly, is a little hot, about 68 to 72 degrees during playback a hevc 4K Hdr movie. Is it normal to heat like this?
How is your temperature?
Yes, a temperature 68-72ºC below 75ºC (theoretically 90ºC) is not bad. The temperature depends on the heat dissipation capacity of your TV Box (I have another TV Box that works below 55ºC to which I changed the heatsinks). It also depends mainly on the screen resolution, the order of resolutions from colder to hotter could be: 720p50hz, 720p60hz, 1080i50hz, 1080p50hz, 1080p60hz, etc. To a lesser extent it depends on the processor load in normal use, except the games. I use a resolution of 1080i50hz on my KIII Pro for this reason.
Many years ago, when I studied the physics of thyristors used in power control electronics, the heatsinks were calculated to never exceed the maximum temperature of 100/105° C.
This knocks off 10C off my box.