Games Lagging With Direct X Update

I've been playing PC games on my new laptop for a few months now, all of which can run on Direct X 11. Two games, Saints Row the Third and Civilizations V I run using Direct X 9 mode, which helps me keep my laptop temperature down.Recently, however, I have bought and downloaded a few games via Steam that are older, that only use Direct X 9.0c. When I run any of these games for the first time, Steam will start "installing Direct X...". After that, all of my games run with very noticeable lag. I will lose FPS (going from 70+ to about 20-) every 20 seconds or so. If I perform a system restore to the moment before Steam installed the Direct X, everything starts running fine again.This has rendered half of my games on Steam unplayable because they all need to install Direct X before playing. The only topic I could find with a similar problem to mine was an unanswered thread here: link .