XPS nVidia chipset

yes boht cards must be the same specs RE:  8800gt  etc... , u will need a SLI bridge ,  u can buy one from Dell spare parts or from the net .. to inable SLI  ,  inable it in the nvidia control panle  

u can install another card from any card maker for SLI as long as the specs are the same.  u can install the nvidia drivers , as they are more up to date and have more fixes or inhancements

So I can get the one 8800 Gt form dell and then add in my own 8800 gt as long as they are both 8800GT, SLI enabled and have up to date drivers?

THank you very much!

Dell uses ZOGIS brand. You can see it at NewEgg.