virtualbox.org

I have installed VirtualBox 2.2.0 on a Kubuntu 8.04 host, and have a Windows XP guest which I am starting up in headless mode (with VBoxHeadless). Whenever I connect to this XP guest via remote desktop, the CPU utilization of the VBoxHeadless process leaps from 5-10% up to around 75%. Why might his be and is there any way I can keep it down?

Try disabling clipboard sharing either in rdesktop or in virtualbox.
On rdesktop commandline add:
-r clipboard:off

and see if taht makes any difference.

Thanks for the suggestion. Something else has changed, though, such that it's running at 60-70% CPU utilization even without the remote login. When I sort that out, I'll try the clipboard idea and report back.

I got high CPU usage with XP when I used "Intel PRO/1000" as the virtual NIC. Switching to "PCnet-FAST III" solved that for me. Don't know if this helps you but you could try another NIC and see if that makes any difference.