well you'll notice a little improvement in performance like realblackstuff said,but if you play games the difference would be monumental,you would be able to play demanding games like doom3,KOTOR with ease and a very little boot time.the only condition is you have a good video card which i see is available in 8600 (fx go5200/64mb or ati 9600 t/128mb).also running application for video editing adobe preimere and animation like 3dsmax and maya would be possible and work smooth,if you are interested in that kind of things.your bootup time would be shorter and overall application would execute just a bit faster.BUT if you dont do any of the things above it would be an overkill.512 mb would have been more than sufficient for normal workstation operations and give you more or less the same boost 1 gb would,so it depends on your use.