Use activity monitor
Use activity monitor to see how much RAM your machine is using now. I put 8GB in mine and an Intel X25 SSD. A very snappy machine indeed. But both of these improvements didn't show a great increase in scores in geekbench. But in everyday application it was a noticeable improvement. I now do everything on my Mac Mini, only fire up the Mac Pro for Video/Photo editing or games. With 8GB Ram in the mini I run parallels (win XP) for my CAD system, have pages open and numbers, plus a few messaging programs. It runs fine, very very rarely a spinning beachball, which is almost always due to flash.