Foxssil

I have an evga 850bq psu and an Asus Rog strix 1080 gpu. Right now I have it powered by 1 PCIe 6pin + 8(6+2) pin cable. Should I add a second just to take the load of the one cable? I came across an article saying you shouldn't use just the Y split cable that came with the psu.

Is my card sagging and is it normal? This is my first build. Just want to make sure everything is ok. I also have a x370 Taichi which has steel reinforced Pcie slots.