strange FPS/stutter/glitch with dynamic lighting Thread - STALKER Complete 2009 mod for S.T.A.L.K.E.R. Shadow of Chernobyl

i see that similar problems have been brought up here before, but the threads were locked immediately without getting solved. one guy had it solved when he updated his drivers in some obscure way, and then every thread about it after was locked, as if that was the confirmed solution.
it wasnt. i updated my drivers, and the problem is still happening.
i have a computer that can handle much more demanding games, and much more demanding dynamic lighting. the problem is most obvious when hanging around barrel fires at certain angles. it actually glitches the whole game out in a way that normal framerate dropping doesnt do. and it happens id say during 50% of gameplay depending on the lighting on screen.
setting to static lighting solves the problem. but that removes a lot of the immersion for me.
i have a gtx 670, intel i7 3770k, 8GB corsair ram, and solid state hard drive
is there some mod that can apply a different kind of dynamic ligthing without the gimping? or is there some other solution?

how to fix this shadows problem ?
win 7, last drivers, gtx 670