I've done a topic on this a few weeks ago but nothing came of it - I could do with some advice:
I have recently (about a month ago) upgraded my mother board, graphcs card and RAM (spec available on hardware config button) and I now have a couple of issues including choppy sounds on BF2 (just like this sound - http://www.youtube.com/watch?v=bReqZsYt_Q8) and games like Deux Ex and Stalker Shadow of Chernoble crash to desktop with no warning from time to time - which NEVER happened before.
The BF2 sound issue is solved when I turn OFF sound acceleration from DXDiag.
All the above happen when either using my Sound blaster Pro 5.1 or the ADI1986A 6 channel High Definition Audio onboard sound on my ASUS P5PL2-E.
I have the latest Nvidia 162.18 forceware drivers, latest soundblaster driver and as far as I can tell the latest motherboard drivers too.
What OS? Sounds like buggy sound drivers. Turning down (or off) sound acceleration would have been one of my suggestions, but I see you've done this with good results.
When you upgraded your mobo, did you do a fresh install of your O/S? Old drivers and stubs hanging around could cause this too.
XP Prof. The thing that makes me think it's not buggy sound drivers is that I've tested it both with onboard sound (which is actually quite good for once) and my soundblaster and both do exately the same thing.
I did a fresh install (format & reinstall).
I'll try moving the soundblaster but as I said above I get the same from my onboard sound (also the geforce 8800 gts is so dam* big that I don't think it'll fit there but I'll give it a go.).