Are you sure its optimized? I cant compare the gpu performance but when it comes to cpu, poclbm-skc hashes around 50% slower than skeincoin-cpuminer on the same cpu. I dont have much time right now, but I can compare it tomorrow.
Maybe we can create some kind of a benchmark to see the performance of particular gpus?
In my case its:
7950 - 180MH/s
r9 280x 200MH/s
Overclocking can get you another 5-10MH/s
5870 at stock core (850MHz) - 95MH/s
7870 (Tahiti) at 880MHz - 94MH/s
6950 at 900MHz - 103MH/s
6930 at 860MHz - 93MHz
Basically all cards giving around 90-105 MHz on my setup, overclocking doesn't change it a lot. On scrypt 5870,7870,6930 have performance close to 400KHz, and 6950 runs at about 450KHz, so current Skein-SHA2 implementation has 230-280 times higher hashrate than scrypt.
Thanks for the numbers.
Looks like all your cards are also mining about 3x slower than SHA256 coins running on cgminer.
Not sure what is needed to get that 3x speedboost, cgminer has a lot of functions/tricks to be that fast...