I've seen a lot of scattered threads about heat "problems" and decided to create a single thread for discussion. Let's start out by stating when we see the problem, where we see the problem, and to what extent the problem lasts. For me, I noticed the top (probably about 1.5cm) of the iPT4 getting moderately hot (not so much that it burned, but enough to raise alarm) when I was playing Enigmo (some pretty intense physics simulations). I've also noticed it when using Epic Citadel. Next time it happens, I'll use my IR thermometer to measure the temperature exactly. When do you experience it?