i have a ASUS GTX 580 DCII, my GPUZ says 25.0 Gtexel FillRate and 50.0 GPixel FillRate. from other pictures and benchmarks and comparisons from hwcompare.com.....GTX 580 is supposed to be 37.1 Gtexel and 49.4 GPixel....
i'm currently using 310 Drivers and i also rolled back to 296 doing a complete reinstall including driver sweep in safe mode etcetc.. still same thing on GPUZ
i havent seen a performance issue in-game...BF3 still runs at 60fps on max settings, diablo 3 runs at 200 etc....and overclocks dont work using msi afterburner...just resets when i go play a game...
Core i7 3770k
8GB Corsair Veng
western dig blue 500gb
also using 2 8 pins for power on GPU