Just a quick side note, I've got a 7/8 year old iMac 20", at the time I had a ram upgrade and a few other add ons but that still handles Photoshop, autocad, lightwave rendering and a few other tasking duties in its stride. It's still as quick as the day I bought it home too. I've had the back off a few times to just clean in there when it starts fanning heavily and it's back to normal again. Really really pleased with it.