uh...i understand that it gives you better performance...i can't say by how much but maybe if i tell you what it does it could give you better insight..idk....but anyways with fastwrites on it allows your cpu to send info directly to your gpu with using up system memory...but i guess that isn't necessarily a good thing in all cases...
well, i think i remember someone saying that for Nvidia cards, its best to leave it off, and for ATI cards to leave it on, or vise-versa. i'm not sure and thats why i created this thread.