^
Twofold imo-
1. Amd's performance was lacking because of GCN, it's not an excuse from me but that's why, they probably could have waited another couple of months to get better, but that= zero sales leaving Nvidia selling the top dog aka 580.
2. The low clocks, because they
had to ship them with low clocks in order to get them all out the door.
There is a new power delivery feature in the 79's that enables more cores to be used instead of binned, 79's come on different stock voltage- some on very low v and some that
[email protected].
The lower the v, the better clocks on air but they are all limited to +1.25v.
If the new feature wasn't there, they would have had to bin a lot more full fat working chips into 7950's, rather than sell them all as 7970's, so the faulty 7970's could get shaders lopped off and go into the 7950 trays=less faulty cores.
There is an AMD tech on overclock.net that explained the power thing, but if you want to read about it-you need to find it yourself.
I also doubt the GK110 in the 680's, as Nvidia were/(maybe are) still struggling for yields, if it doesn't get a price reduction, then it may confirm the yield problems-unless it is the fact that they are selling by the bucketload.
But AMD
are selling by the bucketload at the moment, unless Nvidia do a price shake up soon to come in line, AMD will only sell more and gain market share and investors will hit the roof!
Nvidia have a diamond chip on there hands, hence a mid core gpu auto overclocking like a beast on high voltage(hence the lockdown), it must have scared the life out of AMD as that's the best they have.
If they could have got it out, I
guarantee you it would be out, as technically(I know there's nothing in it) with the GHz and driver improvements, for the first time in years, AMD have the fastest single gpu on sale, and Nvidia won't be happy one little bit.