Like I said, when I bought my iMac back in '06, I paid the extra $170 to get the 3-year AppleCare plan - which basically covers it for 3 years. I'm about 3 months from the expiration on that, which i guess is better than being three months *after* said expiration, given the circumstances. I'm cashing in on that now.

I took my iMac in for repairs today. While the reinstalls seemed to help its performance, it didn't (as i feared) fix the real problem. I have since run some tests and diagnostics and determined that the video ram is unstable, mostly when operating at high load - or more specifically, at high temperature. The thing runs hot when it gets going - up to 63 degrees celsius - and it just doesn't seem to be able to take the heat anymore. Once it hits 58 or so, it will fail diagnostic video ram checks frequently. At 60+, it's every time.

I don't know what temp the iMac's gpu *should* run at, so it may be that it's running unnecessarily hot. Installing a fan regulator and bumping the baseline up a few hundred rpms does keep the temperatures down (and seems to eliminate any video artifacts), but it doesn't seem to make the system any more stable as it will still crash on me - so i'm not sure what the actual cause is or whether i'm merely seeing symptoms of the real problem.

Hopefully I'll know something in a few days.

I'm now especially glad for Kotoko, the new Macbook I got over christmas, without which I would be much more thoroughly distressed at even the temporary loss of my beloved iMac.

~PS