Amd is decreasing the price of 7950 to Nvidia 660 level and giving it a tough competition. I wonder why would they bothered to do so if even a 7850 is better then 660.
I can see several reasons. Most people don't overclock, so MSRP doesn't count overclocking capability. The 7950s were already reaching that price point because several companies who make AMD graphics cards were dropping 7950 prices on their own (I'm not sure why, but some of the best 7950s were heading for $75 under MSRP and that's not even counting some of the sales, rebates, and the $80-150 in freebies that some of these cards came with).
AMD dropped the three free games freebie, so they had to do something to keep value from dropping. The price drop in addition to Sleeping Dogs does a great drop of that. AMD had to combat some of the hype that Nvidia put around the 660 TI. Heck, AMD might have simply wanted the 7950 priced closer to the 660 Ti to make the 660 Ti seem less practical. Similarly priced to a superior card, even when you don't overclock? That sounds like a good plan to me, especially since such people probably have CPUs that aren't overclocked, so the 660 Ti's over-inflated maximum FPS can't mask its low minimum FPS in the averages nearly as well, if at all.
Also, it's a 660 Ti, not a 660. They aren't the same card. Ignoring the Geforce GTX and some other stuff is usually fine so long as it stays within context, ubt losing the Ti means that you're not even talking about the same card anymore. The 660 is a card that is probably going to be released this or next month and should not be confused with the 660 TI.
Another thing to consider is that pricing doesn't always make sense. For example, why do the Agility 4 and the Vertex 4 prices often end up the same at the same capacity despite the substantial performance difference? Why does the Radeon 6970 cost more than a Radeon 7870 despite the 7870 being better in pretty much every way?