hi mike

no sorry mate,sli requires you to use two of the same type of pci-express card,and allthough the basic architecture of these two cards are pretty similar the 8800gtx is significantly more powerful and has a obvious higher memory and bandwidth

personally i would purchase another 8800gts rather than another 8800gtx as 2 x 8800gts in sli would give you a excellent gaming platform capable of 100 frame rates and also it would be more expensive to buy another 8800gtx

for some 8800gts sli benchmarks check out http://www.pcstats.com/articleview.cfm?a… also http://www.tweaktown.com/articles/1088/b…

good luck mike !

Answer:
NO you can’t pair two different models, but you can pair two different memory. for example: You can pair an 8800 GTS 512MB with a 8800 GTS 640 MB because it's the same model. Also pairing two different sizes is not suggested for optimum performance it is possible
Answer:
no you can pair different memory sizes but not different model versions if you go to www.slizone.com there’s an faq that explains basically every way you can setup an sli system and what does and doesn't work. good luck
Answer:
No