Heavy performance loss! What just happened?

Hi, I’m using a GTS 450, two days ago I was notified of a new driver update (at that time I had the following version installed: 301.24 BETA) which is 301.42 and afterwards I installed it. Today I found myself with some free time and I though of playing some of my favorite games.

I started up Modern Warfare 3 first, joined a server and all of a sudden I get an unusual and incredible screen lag (usually in MW3 online I have around 45-50 fps, it has dropped to more or less 17 fps now). I thought maybe it might be some compatibility issue with the new driver, afterwards I opened Skyrim to be sure (usually I can run it on max res and details @25 fps, it has dropped to around 5 fps!) What’s going on?

Before installing the Beta driver I took a look at this article (link), where it says that thanks to NVIDIA’s FXAA, apparently I could have a performance increase of 60%, so I though, why not. Now I get a performance loss of 60% instead, this never happened with any other NVIDIA Gpu I’m using, ever since I first bought one. Am I to rollback to the BETA driver, or an older and more stable one?

Any help is highly appreciated.

Don’t install this driver and, if you have, back it out if possible. I installed and it’s completely hosed my system. Keep losing the display when it goes blocky with screen painted randomly across the landscape, plus for the first time ever got a bluescreen of death from Windows 7. Really bad monkey coding.