If you are using Windows 7 64-bit (Professional), and you are having the same problem as I have, you are in the right place. Occasionally I found that my Windows svchost.exe using high CPU usage, and it doesn’t seems to reduce/stop even after some time. Thus I decided to see which services are linked to that particular svchost.exe.
1) Run Task Manager. (Ctrl+Alt+Del)
2) Under Processes, sort all the program with Image Name (clicking on it).
3) Look for the culprit (High CPU usage). Right click on the svchost.exe > Go to Service(s).
4) It will highlight the services linked to the selected svchost.exe.
In my case, I found upnphost to be the culprit of the all-time-high CPU usage. Once I stop the service by right click on it > Stop Service, my CPU no longer at high level of usage. But it did occur again on the next reboot. Thus, if you aren’t using any devices/special services that utilize uPnP Device Host, I would recommend to disable the service. How? (You make the call either to disable it or not)
1) In Task Manager, under Services tab, click on Services… button at the right bottom of the window.
2) Look for uPnP Device Host, then right click on it > Properties.
3) In the drop down menu for Startup Type, choose Disabled (or other option as you wish). Then click OK. And you can quit Services window after it is disabled.
By disabling the service, my PC Windows 7 has no more high CPU usage by svchost.exe. I am still unsure about the real reason behind the problem, but several findings on the Google suggest that it has something to do with Internet Explorer. Anyway, hope this can help you if you facing the same problem.