The last few months when I approve updates in WSUS, the clients on Windows 2008 R2 seem to have continuous cycles of 100% CPU usage, I assume beings when they are checking in with WSUS. The applications running on the server struggle when this happens many times each day. If I move the Windows 2008 R2 clients to a different computer group that has no updates approved, this all stops. It seems that when there are updates waiting on WSUS, the Windows 2008 R2 clients experience this. This does not seem to be the case with Windows 2012 R2 clients.