I had a g4 800mhz with 512mb of ram and sold it to get a G5. When I got the G5 I got 512mb of ram on that machine also. I noticed it was not that much faster than the old iMac. (I didn't use any programs that are too intense). How much performance difference would I notice if I upgraded the G5 to 2gb of ram? The most intensive app I use is probably photoshop elements.