The onboard noise is terrible and not very good for headphones. So is it possible to stick some sort of sound card in there?
NP5793 <-laptop in question.
There were two options in the past (and a lot of cheap ones too):
The Creative Audigy card for notebooks/laptops, and Turtle Beach had a decent card out at one time. There's also the option of using a dedicated USB sound device as well (either headphones or a break-out box that does audio). Several options... so while putting a new "sound chip" in a laptop isn't going to happen, the PC card or Express Card slots as well as the USB ports all offer potential upgrades.