Hello
Its a 1300w edga gold power supply enough to dual mining with 6x of msi r9 390x?
Not really, you will need to undervolt a lot and maybe underclock, and run low -dcri. Even then you are pushing limits of it, consider dual PSUs. Their total TDP is 1650w. Someone on this forum does it, and it is very unstable.
Overclocked+undervolted to max. performance they use even more than the TDP. A rig with 6x390 (non-X) can easily consume 2000 W...
Edit: so two of the 1300 PSUs would be a good base
