well to be completely honest i do have a dual card setup and i didnt measure the difference between when i have sli running and whne not having it running, but i have never had sli make a big difference anyways so it cant be that different, also i am talking about the crysis demo, so it only maxes on high, and not ultra high like on the full release. also most of the demo your on the shore most of the time or on some sort of path, so there is little vegetation there. but it does work. dont know about your sources, maybe it has something to do with the 4gb of ram i have, but i do only have a shitty processor too, and it still works.