You can enable the 2D driver by using the options:
You add this in Device section of xorg.conf ( results may vary - as I said, it's buggy)
Option "NoAccel" "0"
Option "AccelMethod" "EXA"
Option "MigrationHeuristic" "greedy"
The problem with that is - that it doesn't work well with some programs and can cause X to crash. This is the first time I am trying to debug a graphics card driver, so as of yet I don't know why that is.
The advantage of the crippled driver is that you can work in native resolution of your LCD (if you are using one), 1280x800 for example, and that you get video acceleration (Xvideo extensions).
I am using the driver right now, have been using it for more than a week for that matter. In gnome, with Metacity compositing enabled and cairo-dock I haven't noticed any slowdowns, crashes or abnormally high processor use as of yet.