According to Techspot, AMD wants to release a new card called the Radeon HD 7970 GHz Edition and should be able to manage 1GHz with the wind behind it and if it is going downhill.
Some vendors already offer 7970 cards up to 1,050MHz but these don't fall within AMD's reference specification. However the thought is that by making a 1GHz card official, AMD could once again proclaim to have the fastest single core GPU. The idea is that such marketing would make people thing twice about the Kepler 680, although the differences between the two are small.
AMD increased the clock speed by making improved silicon yields. It claims that it now requires much less voltage to run a 7970 at 925MHz than before so it can be clocked higher.
AMD also said that that the new yields can hit 1,250MHz with little effort. This makes the more cynical amongst us think that AMD is planning to release a few faster cards in the future just by tweaking the spec again.
However with Kepler proving not to be the challenge many were expecting, this probably is not important yet.
So far there has been no word on when AMD might make the GHz Edition cards available. However we are expecting to see them quite soon.