It really depends on your applications. If you have to keep a LOT of stuff in memory (like experimental data from some experiment), then 2GB might be better. b/c a combination of 1GB memory and always hitting the HDD to get the other data might be more time consuming than keeping everything in memory (slower ram) without having to go to the HDD. But, this is a special case and don't apply to lots of ppl. For the typical gamer 1GB is more than enuff. So for u go with the 2x3200 sticks.