It depends on what you're doing. For everything, 512 MB isn't used. For gaming, the more memory you have, the better your gaming experiences. However, gaming is just the extreme. Most current generation apps don't even use up 512 MB. I run 3d Studio Max 7 and all sorts of animation programs on 512 DDR2 ram. I have never used 512 MB. If you're gaming, then the 256 will help.