Not sure if anyone has attempted this sort of upgrade, but I thought I'd report that I was able to upgrade my 20" iMac7,1 (Original aluminum model) with a faster Merom-class processor. Stock: Intel Core 2 Duo T7700 @ 2.4GHz (SLAF7) Upgrade: Intel Core 2 Extreme X7900 @ 2.8GHz (SLA33) I figured that this would likely work as Apple sold a 24" that year with the Core 2 Extreme X7900 as an option. Just so you know, it detects it in Mac OS X as a Core 2 Duo @ 2.8GHz and not an Extreme. Not sure if 10.6.8 and the 24" model detects it as a Core 2 Extreme or Core 2 Duo either. I'm including screenshots from Windows Experience Index scores to give you an idea of the boost in performance both in the processor and the RAM. I would have rather used Geekbench in Mac OS X, but their benchmark list is throwing a 500 error at the moment. FYI. I picked this processor up from a seller on E-bay for $80 + free ship.