Ive recently started overclocking my GPU which is the 6990 i think its still on factory switch of 375 watts i overclock it from 830mhz to 930mhz clock and memory 1250-1450.
yet i dont even have to change the voltage from 1120mv to 1175mv is it just a good Gpu/lucky Di.. oh and i have the settings on catalyst locked so they dont interfere with my msi AfterB and Msi is on Mv1120 setting
YEP!.. Just like the 680 classified and such.. they come with a high binned GK104's. Just like the Super clocks. and the FTW's.. but the manufacture may by accident put a decent binned chip in a a lower end card and it may overclock better than a card 1 tier higher.. SO as you said. its luck of the card from the factory!.. But
Remember to keep eyes on temps. the 6990 can get warm even on stock. most dual GPU cards are
i got 85 C because i had heating on in my house so its like 10-15 c higher some times but yea when i play Crysis 2 not crysis one crysis one never goes over 75 but when its on max settings everything on crysis 2 i get 85C with fan speed 60% when i had fan speed at 50% i was getting 99C so i uped it 10%