my specs are/ cpu:opteron dual core 165@3.ghz 2x1mb cache //2gig of ram@430mhz// 256mb 7950gt can oc to 700core and 1630 memory/motherboard asus a8n32-sli deluxe what kind of settings should i set crysis to run smooth?

You should be fine with medium to medium-high settings.

No one can run crysis with everything maxed out, even with the best rig with over 50 fps.
I have 8800 gtx, 4 gb memory, vista 32-bit, and 2.13 ghz core 2 duo and I have set everything at very high besides shader set to medium and no AA. And I get about 20-25 fps which is very playable. Not the best performance I was hoping for with my specs but there is nothing we can do right now for it.
so play with your settings around a little bit and when you get around 20-25 fps you should be good.

I got a feeling that the rumored geforce 8900 can.

well, two 8800's can come close ;) and my x700 pro runs it medium-ish