[fritsch]

NICE!

proof accomplished - what a shame. The USB ports get flakey under high load ...

So when watching LiveTV simultaneously and using Deinterlacing, which causes high cpu load, that issue happens more often. An external powered hub does not help?

Edit: Try to debug usb. Pixelation should be less likely, when you turn of deinterlacing (though, you don't want that).
Edit2: You should see the pixelation also in vlc (when watching the channel on both machines in parallel)
Edit3: Play with the max cstates and try with 3 first
Edit4: Try a voltmeter on the power supply. I suspect, that we see some "savings" at the wrong parts :p