A customer of me use 4 of those http://www.mindfactory.de/product_info.p...10278.html , the aircooling system is very quit and the card have a big oc potential , stock 1ghz , some settings 1.1ghz s+table.
HIS Radeon HD 7970 GHz Edition IceQ X2 Aktiv PCIe 3.0 x16 (Retail)
HIS Radeon HD 7970 GHz Edition IceQ X2 Aktiv PCIe 3.0 x16 (Retail)