HD 7970 will be down $479 to $429 while HD 7950 cards will go for $349 instead of the earlier $399. HD 7870 will sell for $299 instead of $349, so it's a nice $50 cut for all these cards.
Apparently, XFX and Sapphire are expected to launch their iterations of the HD 7970 GHz Edition next week. The 7970 GHz Edition is expected to ship at 1GHz for the GPU and 6GHz for the memory, which is 75MHz and 500MHz higher, respectively, than on the HD 7970. The card comes with AMD's PowerTune that boost the card to 1050MHz.
The GHz Edition's performance is expected to bring about 10 percent overall advantage over the original HD 7970. The card's consumption isn't expected to be significantly higher, apparently due to the 28nm process improvements in TSMC, but it will be higher.
More here.