Hi again! I've been keeping an eye on iStat Pro's temperature and voltage readings. Can a CPU use NEGATIVE wattage (e.g. -1.81.W)? It claims I have two northbridges. (there should only be one NB, and a southbridge.) It reports 0 amps being used for both. And given the fact that, a manual feel of the rear of the iMac (24", early 2009, running Snow Leopard 10.6.1) was uniform up top, and nowhere near scalding to the touch, is it possible that the temps, amps, watts, and other values are being misread? (or could the heatsink on the NB be poorly mounted, which I'd think is unlikely...) Lastly, how fast can the built-in fans get? My CPU fan is running at 2553RPM, HD fan is at 3583RPM, and DVD fan is running at 2717RPM. Note: NB1 is currently at 62C, and NB2 is at 49C - I ramped up the CPU fan to 3000RPM. CPU is at 39C. The only other component to begin to approach the temp of the NB is the GPU Diode, at 51C. Ambient room temp is 30C (appx 85F). I'm sure my iMac won't fry anytime soon (so far I only do photographic and web site design, some flash/after effects development, but nothing constantly heavy), but even when I used Windows PCs, I aimed to keep all temps as low as possible. Thanks again for taking the time to read this post!!