Onboard NIC and sound card use more CPU?

I've been trying to figure out ways to get a few more fps from my games (America's Army )

So i'm wondering if the onboard NIC and onboard sound card put more strain on the CPU then "regular" ones.

In other words, if I disable them and put a "real" sound card and NIC in the PCI slots, will my CPU have less load?

Thanks for any replies

 

Yes, the cheap ones use the CPU, however I belive in the nForce mobo's there is a chip for these periphrials (the southbridge does it, i think), so there is little extra CPU usage. This equates to having the same performance as a PCI card.