As much as possible, try not to play SA with an internal video chip, as it would lag... I have a GeForce 7300LE, 256MB on my system, which is capable of high-def mods to some extent; however, it will lag real time if you use Boris V.'s ENBSeries mod and some other stuff, especially if you don't use the minimum settings. If your board is a Socket 775, you can directly upgrade to a dual-core CPU, which is a better stretch than a single-core one...