Starting about 3-4 weeks ago, we began to get complaints that some of our users PCs (Windows XP) were running very slow and they were unable to work. We found an instance of svchost.exe using over 200 MB of memory on machines that had only 512MB RAM. Upon ending that processs, the wuauclt.exe process mem usage would begin to climb to the same levels. Upon ending that process, the machine worked fine until it started doing the same thing again after a few hours. Ultimately, we turned off Automatic Updates and have had no problems with the machines we did that to. We used Process Explorer to examine the svchost.exe that was causing the problems and found it was related to Windows Update.
Periodically, another machine will start having the problem, but not all of them. My computer at home began to experience it after installation of SP3 and subsequent updates. I have reports from other users that they are experiencing the same issues on their home PCs. We have checked and rechecked many of these PCs for viruses or trojans and found nothing.
Based on my Google searches, we don't seem to be the only ones experiencing this issue over the last month.
Any ideas about what's going on?