Any idea why the thermal paste on the iMac video card's two RAM chips is the white spongy type, instead of something like Arc...

My niece's iMac 7,1 (Mid 2007, 20 Inch, 2.0 GHz) is crashing and freezing, usually soon or immediately after startup. Sometim...

I've already asked this in the http://meta.ifixit.com/ section, but in case more, or other, people check in here at the Answe...

Carlos, in case you see this, I'm curious how this CPU swap went. My thinking is that if the heatsinks aren't dramatically different in size, you're probably fine with the heatsink that came with your slower CPU, and if/when the faster CPU gets hotter, the iMac's fans will just run longer. Of course, hearing the fans more often might get annoying, if you're the type that's bothered by that.

Thomas, I don't know if you got this problem resolved yet, but in case you haven't, maybe this will help: I'm currently trying to diagnose an Intel-based iMac, Mid-2007 2.0 GHz model, which is currently playing the same symptoms as yours is/was--the same error beep sequence, kernel panics, runs sometimes, etc. I managed to get the Mac to run long enough to allow me to install a thorough memory testing utility called Memtest onto its hard drive, which you run in single-user mode at startup. It kept displaying RAM errors, even with known-good RAM boards, so I felt it was likely there was a problem with the RAM-controlling circuitry on the logic board. So, I ordered a replacement logic board. That didn't help. Swapping logic boards with the supplier requires that you first remove the CPU and GPU chips before sending the supposedly bad logic board to them, and installing these chips onto the replacement logic board, so the only remaining part from the Mac I'm working on, that's likely to be the cause of the probl...