audiodg.exe performance issues

I'm having some serious, and confusing, issues with this audiodg.exe
program.

Recently my motherboard went kaput, so I installed a new one and reinstalled
Vista Ultimate. After that, I started noticing audiodg.exe acting up. I had
never noticed it consume any resources in my old installation of Vista
Ultimate RTM, but now it's using anything from 15% to 25% of my CPU when I'm
playing music, and sound crackles unbearably when I'm trying to do
something.

I'm using the same audio card as before for playback, a SoundBlaster X-Fi
XtremeMusic. The new motherboard has the same built-in SoundMax audio
device, the only difference is my motherboartd is now based on an SiS
chipset instead of an Intel chipset.

Nothing else has changed. I'm using the same version of Vista, same apps,
same memory, same CPU, same video card, and same hardware drivers (except
chipset.) I've even gone so far as to disable my SoundMax device, which I
normally only use for output to my TV. What in the world could be causing
this problem?

- Jacob Rens