^^ Reviews suggest that the gtx 590 perform better below 1080p. At 1080p they are kinda equal. Beyond, the 6990 is better because of higher memory capacity. but who the hell buys this card running below 1080p
This is at stock. At overclock, the 6990 destroys the GTX 590 since the 590 seems to be limited at 770 to 800mhz overclock while yielding poor benchmarking scores. Anything beyond blows up the card. The 6990 on the other hand have gone to 1Ghz on air. Loud at that frequency, yes, but stable - yes! Reviewers indicated that without the thermal constraints (since waterblocks are still unreleased) the 6990 can still go beyond 1Ghz.