IMO the 6870 is factory OC'd. Sort of. Using the old AMD approach with some of their older CPUs (6000+, 6400+) where the default clock speed is so high theres little room left for OC'ing. I looked for OC results for these cards but they're conspicuously absent from most reviews. Legitreviews is one site that tried to OC the 6870 but only managed to squeeze a measly 40mhz out of the card. The 6850 fared better though. So imagine if Nvidia had taken the same approach with the 460 and 470 using very high default clocks leaving only 40mhz of OC headroom left. The cards would be quite a bit faster obviously. With that 900mhz default core on the 6870, AMD appears to be pushing the card near its limits.