While I know that this isn't much more that a "Don't do that" suggestion, have you tried moving away from those AC97 sound chips and getting a real dedicated sound card? There's a reason the AC97 chips are installed on the mother boards - they're cheap. This is a lessen I learned over 4 years ago. Most of my audio tools produced junk sounding output - Cakewalk, Sound Forge, ACID Pro. I moved off of the built-in audio and added a dedicated sound card and I quickly discovered that - A: My system was more stable, B: My software glitched less, and C: my sound was improved immediately.
For now, I use the E-Mu 0404 and 1010 with their ASIO layer on the Windows system and the M-Audio MobilePre USB and the PreSonus FirePod on the Mac (The Firepod has just been dropped to $499, BTW).
I realize that the Firepod is a bit of a financial stretch for many, but you can probably find an E-Mu 0404 for under $100. Check out Musicians Friend:
Muscians Friend E-Mu 0404[edit - added note] If you do add the dedicated card(s), don't forget to disable the AC97 onboard sound if you possibly can. If it's enabled, it uses Windows resources even if you're not using it.
Tim