I think it's tiny difference (~0.7%), and I'm still testing the stability of both drivers.
For me, stability is more important than performance.
I think AMD has tweak some settings toward 7970.
....
7970 with Freq/Mem as 1125/975| Driver | SDK | Performance |
| 12.3 | 2.6 | 660~666 |
| 12.4 | 2.7 | 655~661 |
That's what I was looking for. So even with a 7xxx series card the new version is still slower? Is this an SDK issue, or you think it's just that current kernels are not written for 2.7?