I want to know how much of a factor this was as well.
The 660ti was overclocked to 1900, the 7950 was overclocked to 1700mhz.
I'd think that most of these cards use the same ram chips, making the 670 sample somewhat of a dud. The fact that it had a good core overclock, but a poor memory overclock, likely affected the results, but by how much? It would be interesting to see how well a similar 670 with the memory clocked at 1700mhz or higher would fare.