[solved]VirtualBox slows down Vista host networking severely

[shilbert]

Hi, I'm running VirtualBox 3.0.6 on a Vista x64 host. I have a gigabit ethernet LAN, and normally iperf & file transfers show respectable gigabit ethernet type speeds between physical hosts -- over 500 Mbps. However, when I have a VirrtualBox VM running on my Vista x64 host, communication between that host and other physical hosts becomes extremely slow -- around 50 Mbps. Communication between the guest and other physical hosts is also slow. This happens even when I do not have networking enabled on the guest's VM configuration (no virtual ethernet adapter.) When I close the VM, the gigabit ethernet speed returns again. I have tried Ubuntu 9.04 and Windows XP SP2 as guests, and both exhibit the same behavior. Does anyone know if there is a way to fix this, or should I be filing a bug?

EDIT: Just to be clear, this does not appear to be a simple CPU loading issue. The host is plenty beefy (intel Q6600, 2.4 GHz) and the guests are idling when I'm doing the tests; no CPU spikes are visible. I can see this happening with iperf alone so it is not a disk read/write issue for file transfers.

[shilbert]

Never mind, this does not appear to be VirtualBox's fault. Apparently any program that uses audio does this. I guess this is some kind of conflict between integrated audio & networking :/