High CPU utilization of inactive Windows virtual machines

Problem: My server's CPU utilization high when my Windows virtual machine is mostly inactive.

Workaround: To determine what HAL your virtual machine is using, then determine if you are running with the correct vCPU count for the HAL:

1. Right-click the My Computer icon, and choose Properties.

2. Click the Hardware tab.

3. Click the Device Manager tab.

4. Double-click the Computer icon to see which HAL is currently loaded.

5. In the vSphere or VMware Infrastructure client, click on the virtual machine, then click the Summary tab and see how may vCPU's are configured.
   If you have 1 vCPU and your virtual machine operating system is configured for a Uniprocessor ACPI, your configuration is correct. If your virtual machine operating system is configured for 2 or more vCPUs and it is running with a Multiprocessor ACPI, your configuration is correct.
   Note: Downgrading the HAL from multiprocessor to uniprocessor is not supported by the operating system vendor, Microsoft, and as such it is not supported by VMware.

More Info:
http://kb.vmware.com/kb/1077
http://support.microsoft.com/kb/309283/en-us