Nvidia apparently "dumbed down" the new 6xx series capabilities focusing instead on game related features. They are not totally slow but slower than the previous gen. Since I do very little GPGPU on my system and need a gaming card I will get the 6xx series. While users needing CUDA at a fair price should get the 5xx series or get raped by the Quadro cost. I assume Nvidia did this to differentiate their lineup. You shouldn't let the higher/ lower number thing bother you. GTX570 is most likely what you want. A GTX580 requires too much power trade off IMO.