I've got a brand new (base spec, with 8GB RAM) Mac Mini with XBMC. It works absolutely flawlessly in every respect, and plays anything I throw at it, with barely any CPU usage or noise at all.
The only problem I've got is that occasionally after I've finished watching something, and I pop it back to the home menu ready to use another time (I leave it switched on), after a while I'll find it sitting on a black screen with the CPU fan screaming away, and the device itself rather warm. I can either press the power button or press a key on my bluetooth keyboard to get it back to normal again, usually this works. I think only once have I had to do a hard power-cycle.
Can anyone shed any light on what's going on?
I don't have it set to go to sleep or activate a screensaver.