Yesterday Steam and Counter-strike Source both had an update, mainly making the "friends" messenger more like other instant messaging applications. I couldn't care less, but after that update steam consumes like 50-70% of my CPU in IDLE mode, which makes playing games like CS:S that rely heavily on the CPU power almost impossible! The game is 3 years old, so is my PC and till yesterday it worked perfectly. Now I have less than 20 FPS on an empty server, which is kind of unnacceptable

Has anyone had similar experiences, or is it maybe just a problem with my steam? I'll delete all the stuff and let it re-download it, but I doubt that helps...
Thanks anyway!