R9 280X uses older version of the Overdrive API, which isn't fully supported by PhoenixMiner. We will add this as well as many other hardware control features in PhoenixMiner 3.6 (and no, it won't take as long as 3.5, which was delayed a few times by some unexpected events).

   Yes, unfortunately it is not the same with every card. You can try changing (lowering) the core and/or memory clocks a little as this may help with the green kernels hashrate as strange as it seems. Another option is to try -clkernel 2 but it rarely has significant effect whenever the green kernels are used.


   You are quite right. So, we will enable the green kernels on gfx804 too.


   We are testing with Ubuntu 18.04 now, it works fine with AMD cards. Please note that there is no support for hardware control options (-cvddc, -cclock, -mclock, etc.) under Linux, so you have to set the clocks with some other means.


   Shouldn't be, we usually get the same gt values every time with maximum 1-2 gt difference between the runs. If you suspect that the auto-tune is the problem, just put the best found -gt values in your config.txt or in the command line.


   Nice to hear! We are already working on PhoenixMiner 3.6.


    You can use the -cvddc command-line option to specify the voltage in mV. For example, -cvddc 850 will set the core voltage to 850 mV.