I'm experiencing huge host CPU usage with an idle vmware guest. Host: Ubuntu 10.04 32-bit 2.6.32-24-generic-pae. (Very new install, i.e 24 hours ago) Hardware is Dell XPS M1530 laptop, 4GB ram. Intel Core II Duo T9300 2.50Ghz The virtualization setting "VT" or something is enabled in my bios. Guest: Completely fresh install of Windows Vista, upgraded to latest SP2 and all windows updates installed. 1024 - 1512MB ram allocated. Absolutely no other software installed on it, apart from VMWare tools. Situation When the guest is doing absolutely nothing, I watch with sysinternals process watch on the guest. This shows that system idle process is between 70 and 99%, usually around 95%. No actual process doing anything. On the host, I watch with top, I get cpu usage of 20% - 80%, usually around 30%. What I have tried Single and Dual processor available to guest - no change. Turn off all peripherals to guest - no network, drives, usb etc - no change. Turn off 3d acceleration for guest - perhaps a small improvement, or no change. Upping allocated ram to guest from 1024MB to 1512MB - no change. Yelling at vmware - no change. I have experienced a similar issue in the past, which was solved by setting the guest to have 1 CPU. This time that hasn't worked.