To overclock the PNY GTX 570 today we used Afterburner 2.1 beta 7 which is based on Rivatuner.
We managed to get an 89mhz core clock increase from 732 to 821 MHz and an additional 200MHz via the GDDR5 memory boosting it from 3800 MHz to 4000 MHz effective. While these are not massive increases over the stock values we gained an additional 385 points in 3DMark 11.
The overclocked core and memory speeds allowed the hardware to generate an extra 2 frames per second on minimum frames per second and closer to 4 frames per second on the average frame rates.