Ensuring SLI Video Cards are recognized in Vista

[D-Ho]

How can I ensure that Windows Vista is recognizing my 2 video cards in SLI??? I am running 2 x Nvidia GeForce 512MB 9800 GTX+, but when I view the vista performance report, it shows only 512MB of dedicated graphics memory. The total available graphics memory is 2556MB and the shared system memory is 2044MB. I have the latest Nvidia driver's (7.15.11.7824) and am running directx 10. In the Nvidia control panel, I have SLI enabled. I run the Performance tests for Vista and I score 5.9 on everything, but memory. I score a 5.8 and I have 8GB installed???!!! And when I run Flight Sim X or Crysis, I get major lag, or should I say about 8-12 FPS. I know these games require a lot, but this is ridiculous. Any ideas??? This is a 2 month old computer and there is nothing installed on this bad boy except for those two games and all the updates required. I know this is two questions built into one, so I am sorry about that, but any help is appreciated.

System Specs:
Vista 64bit
Intel Quad Core Q9550
EVGA 780i Motherboard
4 x 2GB Corsair XMS2
2 x 512MB Nvidia GeForce 9800GTX+ SLI enabled
500GB SATA-II 3.0GB/S 16MB Cache 7200RPM HDD
3 x Acer 19" X193w+
Matrox Triplehead2Go Digital