This behavior has been bugging me for a while. When I leave my computer alone for a few minutes and my monitor goes to sleep, some process starts consuming a bunch of CPU time. I can tell that my CPU is being used, because my CPU's temps rise and the CPU fan speed increases to compensate. I've tried using perfmon to track down the process using the CPU usage, but Windows' performance logging is worthless and I wasn't able to find anything conclusive. Does anybody have any ideas what's causing this behavior? This has happened across multiple machines, so I'm pretty sure this is something internal to Windows, and not something caused by 3rd party software. When my monitor goes to sleep, my hard drives start going nuts as well, so I'm guessing this might be either the search indexer doing its thing, a quick defragmenting process, or the Windows memory manager paging out to disk.