I feel that for older cards, the 5x.xx series provided the best optimisation. For my old PC with the MX440 I am using the 56.72 which performs quite well and better than the 6x.xx series. I then did not bother with 7x.xx or 8x.xx drivers. On the other hand with my 6600gt, the 81.95 gave a pleasant performance jump when compared with the 77.77 I was using, even though it was widely believed that the 8x.xx releases were mostly for dual core / sli systems. So I may update again when future releases occur.