The on board sound is equivalent to an $80 - $90 sound card so most are just cointent to stick with that.... I wouldn't replace it unless I was getting near the $200 price point
October 26 Build
MoBo:Max VI Formula
RAM:16GB Mushkin DDR3-2400 10-12-12-28
GFX:2x Asus GTX780 DCII
HD: 2x Seagate 2TB Hybrid SSHD
SSD:2x Samsung 840 Pro 256GB
PSU:Seasonic X-1250
Case:Phanteks Enthoo Primo
OS:Win 7 Pro-64
Monitor:Asus VG248QE Black 23" 144 Hz
Optical:Asus BR Burner
KB: Logitech G19s
Mouse:RoG GX950
Fan Con.: Six Eyes
Cooling:420+280 Alphacool Rads, 35x2 Pump, EK CPU/ GPU Blocks, Acrylic Tubes w/ BP Fit