VoIP / Voice Chat issues

I've seen a few posts in these forums about people having VoIP and/or Voice Chat issues with Vista. I just installed Retail (not Beta or RC) Vista Ultimate and I'm having this issue too.Here's the situation: When using a Voice Chat software title, such as Google Talk, and chatting through a USB headset, the sound is fine unless there are any other programs that use some CPU time. When other programs vie for CPU usage, the voice on the VoIP application becomes distorted and completely incomprehensible on both the sending and recieving end. Playing a full screen game makes it real bad, but I can simply open a website and scroll up and down really fast and cause the problem too. You only need to bump the CPU usage up a bit.The common response to the issue has been to update drivers (which I have done, to no avail), but there have not been any real solutions posted. Also, this problem does not happen in Windows XP on the same machine. On my computer, when I had XP installed, I could have Google Talk open, voice chatting with someone, and open any other programs and do HEAVY multitasking with no sound issues or loss ever. In Windows Vista I can't really run ANY other programs other than Google Talk or I risk sound corruption.This is a serious problem. I have been testing vista since Beta 2 and this issue has occured throughout all versions. I depend on the ability to use a Voice over IP application, such as Google Talk, while using my system. If this cannot be resolved, I'm going to have to reinstall Windows XP. I hope someone can help. Thank you.