Hi, ZOTAC GTX 1070 Mini 8GB or SAPPHIRE NITRO+ RADEON RX580 8GB?, i know zotac 1070 mini is better performance in term of the spec and also slightly expansive then rx 580, but i have a 1080p 60hz AMD Freesync monitor. Currently using sapphire R9 270x 2G. Do the two GPU above worth to upgrade from my current GPU?