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Whats the point of a 595gtx, which with 875Mhz clocks would be more than 2x580gtx's anyway, and a Mars 2x580gtx, you're basically looking at two identical cards with different names?
Its like AMD making a new 6990 but calling it a 6970x2, seems a bit mental to me. You'd think the 580gtx based one, being a limited 1000 card run would have to have higher clocks than a "normal" 595gtx otherwise what makes it limited edition and better.
That means they'll be wanting to go 900Mhz+ on the limited edition version but its essentially making a card with 580gtx in the name faster than a card with 595gtx in the name.
I reckon the two idea's will become one limited edition 595gtx mars edition jobby.