Hi,
Would you recommend buying RX580 rx 580 red devil 8GB?
Also will you power only 8Pin or need 6 Pin+8 Pin need to be connected to PSU?
Thanks
Of all my cards the XFX and PowerColor are the worst. So no I would not recommend. If I had to buy again I would stick with Sapphire and MSI in that order.
For the other question, to mine XMR/Cryptonote currency you don't need that much energy so a single 8 PIN connector is usually enough.