Recommended system requirements for large naval maps

[Gladenbach]

The upgrade is done and it is defintely the Graphics-System. Though, Civ V has very stable Crossfire Support, two 6850 are still very slow. but stronger than two 5770. For My resultion I assume I need two 6970 or better two 6990, so when I not play, I can use that system for Bitcoin-Mining

Thx for the support and have nice time with Civ IV / Civ V