If I bought a CRAY super computer will CA be faster?

[Sledge]

Make sure your Power Supply is up to handling such a card. Many of the PCIe x2 cards need a 4 or 6 pin power connector. Even if your Power Supply has such a connector, you need to make sure you aren't already running close to max with other peripherals in your system.

Dell power supplies are generally better than their stated rating, but it would be advisable to check Nvidias recommended spec and (as Lew also says) what Dell says you can run.