Well one is very nice and the other is a little nicer, there is a big difference in the ram though. Im running 2 GB of 667 ram but If it were 800 ram my computer would be twice as fast.

Dont let anyone fool you, I would rather have 1 GB of 800 ram than 2 GB of 667.... Go for quality over quantity.

Cubase will run very well on a duo core and 2 gigs of whatever.

If the motherboard has an 800MHz front-side bus, then fit 800MHz memory. You can fit 800MHz memory to a 667MHz FSB system, but it will run at 667 not 800.

My information is that Cubase is a single-thread application, so the system will not benefit from more than a duo, as it's best to avoid running other apps at the same time.