I have had the M8 for approx 6 months now. Recently the playback has got very 'choppy' specially on 1080p films usually resulting in the video skipping forwards to the end of the video even after only 3min play. I came to the conclusion it has something to do with the cache. I tried ALL the usual cache tricks but nothing worked. During one 'diagnostic' phase I was looking at a video with the OSD highlighted (pressing 'O' on the keypad) and noticed that only 2 of the 4 CPU's were showing (CPU 0 and CPU 1) I reset the whole box and rebooted. Looking under 'System' I now had CPU 0, CPU 1 and CPU 2 all showing some action but no sign of CPU 3. Is this normal? Is there a way of testing the CPU's ? The picture is still a little jerky even with 3 CPU's. Anybody have any ideas?