I have 2 VMs running as guests on a KVM virtualization platform running on Ubuntu 10.04. One VM is an Ubuntu 10.04 system, the other is a Windows 7 system. When both machines are completely logged out, the Linux machine uses 1% CPU, the Windows one 45-50%, according to top. The graphs in virt-manager seem to back this up. There's nothing installed on the Win7 image that would be running in the background; its as fresh as can be.
Why is the Windows VM using so much more than the Linux VM, when both are logged out and idling?
I installed the guest with paravirt storage and network drivers from the get-go. I don't believe there are any other drivers that I'm missing, am I wrong?.
According to the guest's task manager, it is indeed idle. Taskman takes about 1 or 2 % of the guest CPU, but there's no other processes taking up any CPU time.