4870x2 crossfirex with 4870 1gb

hey guys, my desktop is now with a Asus P5Q3 mobo and running a crossfirex with 4870x2 and a 4870 1 gb version( q6600 @3.2, 4gb ram at 950, vista 64 bit + ccc is 9.2) , both are Sapphire. it should be really great when playing games but , i don't think it's good as i expected, like crysis , when i turn everything to ultra high ( 1440 X 900), it will lag and it shouldn't be.

So just wanna know my setup is right or not, the mobo got one blue pcie slot and one black slot and i've put the 4870x2 on the top and 4870 at the bottom. And one thing very weird which is my monitor can only got signal with the 4870. And i've tried find out the issue on very sites and forums but no good. So can somebody tell me if i did sth wrong or not or how can i improve my system, thz.

thz for the suggestion but can u tell me how can i set the x2 as my main display? Becaz in my c.c.c., when i look into crossfirex - configure, the graphic adapters just show the 4870 but not both.