[H] Mobo Sound vs SB X-FI Xtreme Sound

[Anthony Q. Martin]

I'm using a Gigabyte p35-ds4 mobo that has "Intel high def" sound. The 
old PC had an SB X-fi Xtreme something or other in it. So far, I'm using 
the sound right off the mobo as I can't see any reason to put in the SB 
other than to clutter up air flow and gen heat inside the case.

Am I missing something here?  Is cpu "overhead" really that much less 
with the SB than with the Realtek ALC889A codec? Is there a significant 
performance hit in games, for example?