I have a Dual 2.3 G5 with 4.5 GB of RAM with a recent upgrade of Leopard. I've had this basic hardware config. since I got it in 06 - so I am doubting the RAM ( from Crucial) as an issue. Here's the rub: I have been having various issues with Leopard (click my name to view some of my posts re: this fact). Now, one of the more annoying issues is: sometimes it will go to sleep "halfway". Meaning - desktop goes away, a few sounds are made by the tower of shutting down - but the fans continue to blow... If I hit the space bar (or any key for that matter - or mouse) it will not resume. I cannot get it to awaken. And most concerning - the fans will slowly build to a frightening level! I let them go (a few minutes ago) for about 5 minutes to see if they would eventually come down or shut off - I had to stop it by a hard restart, because they wouldn't stop elevating!!! I've read around the web that this was a concern for some of the G5's, but I've never had this problem in the nearly two years I've had this. It was only after Leopard upgrade (I installed clean on a separate internal Hard Drive) that this behavior reared its ugly head. Last night, I had finally a successful G5 sleep - but I had to close all apps (itunes, ical, iphoto, entourage, itunes, safari) except finder. Usually I wake up to it on - it apparently wakes itself at some point in the night. Any thoughts?