For all the talk about heat, I decided to get the non-contact thermoeter from where I work and get some actual numbers instead of speculating. Computer: 17" MPB (2.16GHz), 7200RPM HD, 2GB RAM, one of the first batch off the line. Thermometer: Raytek MiniTemp infrared thermometer. Generally tested accurate in our in-house laboratory experiments. Test conditions: Macbook sitting on a "mini-table" that allows air circulation underneath. Room 25C, my palms are 34C for reference. Test: did a yes > /dev/null in two terminal windows to max out both processor cores. Opened an Enigmo2 demo in a window to get the graphics chip up to full speed (tested to confirm full clockspeed) and doing some work. Did light additional work to prompt some hard drive access, though didn't do anything intensive with the drive (like encode video). Also was typing with my hands on the wrist rests to make sure that any heat buildup encouraged by my wrists was going on. Processor core according to CoreDuoTemp was stable at about 83C throughout the test, occasionally flickering very briefly up to 85 or down to 82. Room: 25C My palms: 34C Note: After about 5 minutes of this "full on" state, I heard the fan for the first time EVER. It was on steadily, but not obtrusive--sort of a whoosh sound. Results: Surface temperatures stable after 15 minutes, no change 45 minutes later. *Palm rest/trackpad area 33-35C (barely warm to the touch); areas near the left speaker and directly under the space bar are a bit warmer, about 39--a little warm to touch. *Keyboard itself is measured at 38-40C, although it doesn't feel quite that warm to the touch; either it feels cooler because of the plastic keys, or the temp gun is seeing the surface beneath the keys and skewing the measurement upward. If I put a silicon keyboard cover on, the keyboard is not noticibly warm. *Most of the metal "keyboard stripe" above the keyboard is around 46C, with a hotspot of 59C near the F10 key -- the whole thing is too hot to touch for more than a second. *Most of the underside is between 35-46C--cooler near the front and sides, hotter near the back. There is one hotspot of about 51C near the underside of the F1 key area. Part 2: I quit Enigmo, but left the cores maxed out. Within a minute, the fan had spun down to the point I couldn't hear it unless I put my ear near the computer. Soft "woosh" if I do that. Processor core reading remains the same--83C, occasionally spiking to 85C All surface temperatures remained stable. No measureable differences without graphics chip working hard. Finally, when I reduced the processor use to idle, the fan stopped and the CoreDuoTemp measurement was 65C within 30 seconds. ----- Also, for the heck of it, some power measurements: Adapter plugged in, Magsafe disconnected: 0.0W Computer sleeping: 2.0W Computer awake, idle: 30W Both cores maxed: 60W Both cores maxed, graphics card under strain: 80W. Guess that's why the new MBPs have the big, beefy adapters. They're necessary when that X1600 is cranked up and doing its thing. Although the power saving is impressive, given that the Core Duo can save 30W when not under load, and the graphics chip another 20W. Not bad at all.