Far Cry 2 Problems (Purchased on Steam)

Alright this isn't a rant thread I love this game. I am just having some problems with it and I want to know if anyone is experiencing the same thing or if there are any known solutions.

Specs are in the sig for reference. I am on vista 64bit

When I started playing this game I was using the 8.10 Hotfix drivers, fps never dropped below 50 with everything on Ultra High 1680x1050 and 4xAA. I noticed though that the game would be choppy especially when driving. Not like fps lag, the frames never showed below 50. It's like smooth for a few seconds, then it stops for a split second, then smooth for a few more seconds...This only occurs when in battle or driving which is weird.

So, I uninstall the hotfix drivers and apply the standard 8.10's and my fps now is cut in half at the same settings...high 20's low 30's. The weird stuttering problem is gone now but so are my great frame rates. The game also crashes with these drivers after about 30 minutes of play to the desktop for no reason at all which is annoying since you cannot autosave.

The last problem I seem to be having is the game running in windowed mode when DX10 is enabled. I can apply fullscreen by hitting alt+enter but I would like a permanent fix to that.

That's it for now, do you think the game just needs a good patch or are these problems due to something else? is anyone having similar issues? are there any permanent fixes?

Thanks in advance.