I got my iMac (2.0 Intel Core 2 Duo, 1gig of Ram) in April, and I love it as it is. Once I turn it on, the computer is ready to go in like 30 seconds (including time to log in). To me, that's awesome, and one of the highlights of my iMac. I really don't want to wreck that. However, Leopard looks really cool and I want to upgrade to it. But I don't want to lose the performance that I currently have. So, if I added another gig of RAM, would that make a big difference? Or will Leopard even slow down my iMac very much at all if I leave the Ram as it is? I keep reading about how Leopard's 64 bit and I think my iMac is 64 bit, but I really don't understand most of that crap. Also, when I install Leopard can I choose an "advanced" option where I can just not install the things I don't want? I've never before upgraded a computer's OS, and this is my first Mac. I just want to know what kind of impact having a new OS will have on system performance. Thanks for the help!