How can I SLI two graphic cards I have two 9600 nvidia 512 MB

Your card supports SLI technology. You'll need a compatible motherboard too alongwith an SLI bridge. You can check the list for NVidia 9600 compatible motherboards on the link given below.

http://www.nvidia.com/object/support_aic.html

the position would you plug the second one card into? will the second one card in basic terms be sitting on a shelf i do not trust that would help the performance any ! in case you do get a sli enabled mom board think ofyou've got 2 possibilities on your photo playing cards setup! both run both at comprehensive performance in sli or run an really strong card for photos and a second lesser card for physics .

it is obviously you need a SLI capable Board such as Intel BX48BT2 mainboard.

the boarda bove has 2 PCI E slots and it can support SLI

you need a sli enable motherboard and the sli bridge