100% CPU usage with high network traffic

[everwicked]

Hello,

I've got a Virtualbox VM with Windows Server 2008 (1024MB RAM allocated, 32-bit) on it, running on a Debian 5 host. The host CPU has no VT support.

I am having a problem running utorrent on the guest - if it initializes a download with high throughput (server is on a 100Mbit line), the CPU usage immediately goes to 100%. Pausing the torrent drops the CPU again. The same happened with windows update!

I've tried all the different NICs just to see if it made a difference with no results.

Any ideas how to fix this??

Thanks