Hi there, I've been wanting to upgrade my iMac (Mid 2007 20") for a while now and have never gotten around to it. The main reason is to bolster the speed as it's been having a lot of speed issues as of late (freezing up and moving extremely slow.) It's always been a hassle trying to play the Sims 3 on it but I refuse to get a PC for gaming when it's really just the one game (possibly more in the future, but I'm a 360 owner not a hardcore PC gamer.) What I've been told is that the most important thing to upgrade is the RAM. I already have found a replacement and that's the Kingston 4GB (2x2GB Modules) 667 MHz DDR2 SoDimm iMac Kit. Current Status: 2 GHz Intel Core 2 Duo processor 1 GB 667 MHz DDR2 SDRAM ATI Radeon HD 2400 XT Now is there anything else I should/could update to help improve the overall performance as well as the gaming experience. As I'm sure some if not most of you know (especially the gamers) that the Sims will kill a computer such as mine as is when running at full capacity.