Yeah, I've been lazy w/ driver updating - hehe.
I've had the latest downloaded (310.90), but ain't installed them.
There's no major game here that I'm playing right now (performing poorly/underwhelming) that's forcing me to upgrade them.
I didn't even notice how much of an improvement drivers can make until Skyrim that is. One driver update increase my fps by about 5, that's not a lot but I'll take free extra performance any day of the week.
You may also want to test and see how well Physx performs when you use your processor instead of your GPU.