I've noticed my iBook has been running hot since I installed Tiger last week...hot on my lap. I've had the iBook since last August and place it on my lap often hours at a time, and I've never noticed this kind of heat. So I downloaded Temperature Monitor, and here are the readings: Battery: 87.8F Processor Bottomside: 144.1F Graphics Processor Die: 140.9F Power Supply/Memory Bottomside: 124.2F SMART Disk TOSHIBA MK4025G: 118.4F This cannot be good! I can't tell if the fan is running. I don't hear anything or feel anything out of the back of the laptop, so I'm guessing it's not running. Any ideas/suggestions? I'm not a 'heavy' user, though I have Adium, Firefox, Entourage going most of the time.