~100% CPU Usage with little CPU Process utilization

Question

Fresh install Windows 7 on single core desktop. Windows Task Manager:

• Performance Tab: spikes to ~100% CPU usage for long periods (30+ seconds)
• Processes Tab: sum of CPU column is < 4%

Windows Update -> Install Updates seems to cause trigger this event. Is there a simple / clever technique to determine if there are any other services that are significantly consuming CPU usage?

Answer 1

To check to see what Windows service is using significant amounts of CPU, visit this ServerFault answer.

If you're not 100% sure whether or not a Windows service is using your CPU, open Task Manager as an administrator: search for Task Manager in your Start menu, right-click on Task Manager, click Run as administrator, click Yes if a prompt pops up, go to the Details tab, and sort by CPU. You can slow down the update speed under the View menu if the list changes too fast. If svchost.exe is using a lot of your CPU, a Windows service is the culprit, and you need to follow the above directions. Otherwise, the executable shown is the culprit.