I am thinking of getting multiple AMD 6970 cards. I don't consider the 6990's because they are too hot and noisy.
I should point out that the 6970 is PLENTY noisy. If you are going to pool them for "renting" then you will likely get more bang for your buck with the 6990's and good ventilation since they only use one PCIx slot. For me, the limiting factor was that I didn't want to put $850+ into a single card, the 6990 (I could actually get two 6970's cheaper) and it was too long to fit in my case; as it is, the 6970 only has about 1/4" to spare in length.
lol. "6970 is PLENTY noisy", but you recommend me get 6990 as if they have lower noise level?
The 6990 only uses one PCI-E slot doesn't make sense either. The card is so huge that even though u can insert it into one physical slot, but it would take up 3 slot spaces for tiny room of ventilation.