Hmm. The mem use have tested in earlier version of Pscan, and how much photos have you used ? i have tested on around 35 18Mpix photos, will test over next few days, will report....
The 680 should be 3times faster in GPGPU operations, not in games, will believe when use it, because 7970 have around 3,7 Tflop and 680 just 3.1 Tflop in single precision - what is used in Pscan.......
580 around 2Tflop.....