EXACTLY what challenge said. When you are testing it with windows, the computer isn't being taxed... but talking vox through aces high.. you've got a computer that's already being pushed to its limit, and then it's got so push through an onboard sound microphone on top of all that. No wonder it only works well 20% of the time!
The best you can do is run AH with the lowest settings bearable, use gamebooster (or the like) to shut down everything you can on the computer INCLUDING A/V, and hope for the best.