I noticed I was getting lower frame rates all of a sudden so I did a little research and found that wmpnetwk.exe (Windows Media Player Network Sharing Service) was taking up quite a bit of cpu resources. I initially went into services and stopped it and noticed my cpu went down to 1-2% usage. Ran the built-in ARMA2 benchmark 1 and "recovered" my lost frames. Obviously this service is used for file sharing with my network(specifically my son's xbox 360) I don't use it so I disabled it. It literally made 7 fps difference for my rig.
I did a search here on the forums and didn't see any other posts about this. Figured I'd share, although ymmv.