SqlACID's questions

I have a few servers, running Server 2003 Std/Ent and SQL 2000/2005, that I've noticed will start showing higher CPU usages over time. Stopping the WMI service and restarting it will always bring it back down. It's not a huge creep, but after a month it will be around a 10% increase, so even in idle times, it will show 10% cpu usage. We don't use WMI heavily, just a couple of scripts checking service states, and perfmons (does it use WMI?) which is how it was noticed. Are there WMI trace tools? Any other methods to troubleshoot this? The servers that show the symptoms are vastly different, no common elements other than the OS and SQL.