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...
This isn't a pure sha256 coin, comparing it to sha256 cgminer performance is moot, esp in the face of missing optimizations between the two, i'm not the first too point this out. However r9 280x overclocked to 1100mhz 207MH/s
Lets compare Skeincoin with Blakecoin instead, running on AMD 7970/R9 280x at 1170MHz core and 300MHz mem:
Skein (poclbm-skc): 225MH/s
Blake (cgminer): 2800MH/s
SHA256 (cgminer): 700MH/s
Scrypt (cgminer): 700 KH/s (1050/1500MHz)
Moot or not, benchmarking is fun.