it can use 2 cpu's too. the difference between aac encoded at 400kbps variable bit rate is amazing compared to mp3 sound.
I'm so much impress by the difference that I'm reripping my cd collection (lot of cd's)
Edit. I ripped 50 cd's in 2 hours. I ripped them using 2 computers. I used one for the badly scratched cds and one for the good cds.