It looks like adding a usb webcam to the virtual machine causes performance issues for audio devices. This is especially troubling when trying to use a voip client like skype or lync from inside a virtual machine. I've seen this issue on both the fusion preview and the workstation/player preview.
Using the Virtual USB Analyzer Virtual USB Analyzer I'm seeing really high logging volumes whenever I enable video from a usb video device. For instance a normal logging session on fusion 6 would create a order 10megs log file, on the tech preview I'm seeing gigs of logging in minutes.
My uninformed guess would be that the pci-e webcam connection change somehow broke normal usb video devices.