Dogie, in your Ares 256 review you recommended to set difficulty to 16000+ in Ghash.io pool settings. I tried increasing it to 51000 and the miner is now capable of up to 360 MH/s. Two Ares units output 680-720 MH/s, while retaining the same power consumption! Note: environment temperature is 22C.
Made no difference to me. The higher difficulty will be doing is increasing the period you have to run to get an nice average hash rate, and the only time it should make a difference is if the controller is being bombarded / overloaded by too many low diff shares. I don't see any evidence of that happening at 16k.
Thank you for clarifying. I'll test it.