I've noticed that my MK808 is sensitive to being left on...I popped
mine open, to see two patch antennas, an aluminum heatsink and a
piece of copper foil attached to 2 RAM chips. An external antenna
(dual antenna) should be easy to add this with a quick soldering iron...
$7 on ebay. I'll cut up an old heatsink (one with fins) for the CPU,
and find some video ram heatsinks for the other side. I don't know
if I'll bother putting the CASE back on, it doesn't help with cooling issues.