Hey guys, First time poster here, i've been trawling through forums trying to find if anyone is having the same issue as me but with no luck so far, i'm hoping i've missed something obvious and this is an easy fix. I've got a Gigabyte RX 560 4gb(V2 model that has no power connections to the motherboard) that isn't playing nice when being tested at 1920x1080 on my monitor. Basically it runs fine and i can get around my mac with it set to 1920x1080, but if i open a gpu hungry game or a gpu app like opengl extensions viewer and put stress on the card at that resolution the screen becomes extremely glitchy, i've tested it at 720 with no problems but this card should be able to handle 1080 comfortably. A little back round into the tests i've done with no avail. Originally i was testing with dual monitors (both acer s221hql full hd) Tried with a single monitor, also tried with a different monitor (Hdmi on my TV) Tried both hdmi and dvi ports separately, don't have the cable to try the display port, but i'll still need either hdmi or dvi to use as a dual screen setup. Tried different cables between the monitors Changed from Pcie slot 1 to slot 2 Originally tested in 10.13.4 was hoping the update to 10.13.5 would fix it but no luck there either My only thought is maybe because the card has no power connections to the motherboard unlike version 1, that it may not be getting enough power through the pcie lane when put under a load, but you would like to think they thought about this... I've attached some system spec screenshots that may help?