i downloaded a roengine.ini file from a guy who posted it in this forums and since i use it i have almost constant 50-60 fps in game no matter how full it is, well except when to much arty and smoke comes down, than it drops, but never beyond playability.
unfortunately i dont remember in wich thread he posted it, but it was in one of the crash threads after the latest patch when ppl constantly were crashing with low shadows.
i run a amd quadcore phenom 2 , 4gb ram , ati 4870 on win xp prof 32 bit.
i couldnt play the game on any map but gumrak but now i can play barracks with no problems at all.
search for it, i recommend it to everyone and as a sidenote, i have almost no crashes at all perhaps once in 10 hours.