Very choppy after updating drivers?

I run:

2.67 ghz i5
8gb ram
ATI Radeon HD 5800 series card

Previously it was working "okay" but you'd hear my graphics card running pretty hard while I played.

So I started looking on Reddit and googling for tweaks to make and I tried vsync and that didn't seem to do much. The rest of my settings are at the lowest.

I then updated my drives and the game has become very choppy, to the point where I don't really want to play anymore. Just walking through environments you can see the graphics kinda skipping a little bit.

I'm a ranger and when I kite, a lot of times my arrows shoot in the opposite direction (towards the direction I'm running) because the game hasn't caught up and realized that my mouse was back in the other direction.

Anything I can do to fix this?

Still looking for a fix, playing the game is very difficult like this.

You can rollback your drivers to the previous version.