Catalyst 12.7 and 304.48
I hope for NV that their performance in Dirt Showdown is a bug / driver issue of some sort and that they will fix that awful performance with an update/patch. Otherwise, given that Dirt Showdown is the first game to use Global Illumination via Direct Compute, that doesn't bode well for Kepler architecture for next generation games. Hopefully, it's simply a driver/bug issue.
Also, your 1290 mhz overclock on the GTX680 (when accounting for GPU Boost) is very near the maximum capacity of most voltage constrained GTX680s. However, the Lightning version of the 680 should support voltage control for the GPU in the subsequent MSI Afterburner revision as has been confirmed by MSI. It would be welcome if had a follow-up review of MSI GTX680 Lightning vs. HD7970 Lightning with new drivers and with fully voltage unlockable capabilities for the 680 chip.
The 7970 in this review only reached 1165mhz, which is not that great. I've seen many 7970s reach 1230-1280mhz with 1.25-1.3V. As such, I think HD7970 at 1200+mhz will actually overtake the GTX680, while still retaining some key advantages of double precision compute performance, WinZip 16 acceleration, Adobe CS6 acceleration, and 3GB of VRAM. The latest Catalyst 12.7 drivers provide a huge boost for GCN architecture where a stock HD7970 is just a hair behind GTX680 at this point and a 1050mhz HD7970 GE edition overtakes it.
With the added performance increase from the drivers and extra overclocking headroom of the 7970 series, the tables have turned in my eyes, where now I think the better buys are $400 GTX670 or $450-480 HD7970 cards over GTX680. I really don't see any added value besides bragging rights for owning the fastest NV card and lower power consumption for the 680 at this point over an overclocked 7970. AMD's driver team has made up for huge deficits in SKYRIM, Dirt 3, while maintaining its lead in Metro 2033, Alan Wake, Dirt Showdown, Serious Sam 3, Bullestorm, Anno 2070, Crysis 1/Warhead games.
At this point, the last 2 area where NV has the edge are Battlefield 3, by now ancient Lost Planet 2/HAWX 2 and Blizzard games. That's not a lot left for NV to claim a lead in.