I have some experience building my own computers, but I guess I'm not as adept as I thought I was.
I recently upgraded my graphics card and immediately started having sound issues. I'm hoping someone here could help me.  
 
My current rig specs (from memory so forgive me if they're incomplete)
mobo: ASUS P5B-VM  
cpu: intel Core 2 Duo E6320 1.86GHz  
previous card:  ASUS 8500GT  
Ram:  CORSAIR XMS2 2GB (2 x 1GB)  DDR2 800  
PSU: Nspire 450watt Input: 115/230v 10A/5A 60/50hz, output: +3.3/28a, +5/40a, +12/25a
sound card: Creative Sound Blaster Audigy SE 24bit  
new card: EVGA 8800GT Superclocked 512MB  
 
So I edited this for brevity. Installed new card, ingame sound was like playing underwater in an echo chamber, it made the whole game slow and jerky.
 
The card specifies I need at least 26amps on the 12volt rail. This psu only has 25a on the 12v. Plus it's about 2 1/2 years old. Could this be the problem for the sound slow down?