...Linux runs sweetly!
Performance is great - I just recompiled my kernel for the Pentium 4 and you can "feel" how light Linux is on the machine.
Sound is great, and I'm using the onboard 850GB motherboard sound.
Using a geForce MX200, and using Tux Racer as a reference - there doesn't seem to be any problem there.
http://tuxracer.sourceforge.net/index.html
Like the others mention, the only problem you'll have with gaming on Linux is lack of available titles, unfortunately.