From what I understand, the onboard sound will use cycles from your cpu to process the sound. However, in the case with the SoundBlaster Live!, it's not so much the fact that it has its own board but rather that it has its own processor on the card which processes sound. This frees up your cpu when compared to onboard sound. I don't know exactly how much of a difference it will make, but I would imagine not very much. If you're going to get a cheapo sound card just to get more performance out of your cpu, the I would say don't bother. The sound won't be much better, and you probably won't see any improvement in performance. Why not get a SoundBlaster Live! Value? You can pick one up on pricewatch for about $40, and it will sound tons better than the onboard sound.....provided that you have good speakers to go with it.