I have a Reference XFX card (925/1375)
If I let cgminer compile the kernel at default clocks, and then apply overclock, it reaches ~700kh/s
If I let cgminer compile the kernel overclocked, it won't go past ~500kh/s, with same settings/clocks
so I guess those ghz editions have to be downclocked to default speeds at first, and then overclocked after cgminer compiled the kernel
I ran a diff on both compiled kernels, and found binary differences.
OMG... this has helped me tremendously, you're absolutely right that if you let cgminer compile at default clocks it will go much higher with these XFX ref cards, just tried it out. Thank you! (edit: all i'm getting is rejects right now but i'm sure i will get it working and report back)