Ouch, that hurt. I strained my shoulder patting myself on the back...
Glad I could help.
Dynamic lighting is really cool but it eats my card for lunch. They make explosions and muzzle flash impressive but that's where my card would drop to very low FPS. It would get me killed all the time until I turned it off.
On the bright side keep trying new drivers. ATI did an update last January that let me use dynamic lighting BF2142 with reasonable FPS when I couldn't before.
Here's a guide on adjusting the various options so you might be able to get dynamic lighting enables with decent FPS. From all I can find dynamic lighting should not be affected by the CPU performance. The GPU vertex processing ability is the primary limitation. The 1950XT is one of the best ATI has but it's less than half the vertex rate of the newer Nvidia cards.
http://www.tweakguides.com/STALKER_5.html
On ATI tool:
http://www.techpowerup.com/atitool/
I'm using 0.24 on atitool. Click the settings button on the lower right then clcik the menu on the upper right of the new window, just under the Close Wondow X and the drop down will show all the options. Temp monitor is the third item down on the menu.