It was one of those Titanium G4 beasts. My gf called it the "war machine" since the keys were worn to the point you couldn't read most of the letters. So it got way too hot before it even throttled down, and I never saw it shut off from the heat. It radiated heat through that metal... it would almost scald your legs.

I could usually control my CPU use so a magazine could last up to half an hour... but basically I'd feel the warmth coming through the magazine, jump up and switch it with another one from the freezer. Easy peasy.