This has been going on for months now > the Mods here will give you the same response they have been giving for months. Everyone is trying everything under the sun from the newest systems to the oldest. Its a game issue period. I did everything and finally did DDU and installed Nvidia drivers from just before Shadowbringers launch. Some days I can go for a few hours with no problem other days like today every 20 mins. Seems to happen the most when the server-load it high and I'm not really doing much now. It has something to do with FFXIV not being completely compatible with the newer GPU drivers.

Area51 answer: SE is working with Nvidia to make us think we need new machines and people go out and buy new machines or GPU's since new video cards and the like have recently been released much like cell phones when they send you that needed update and magically you phone stops working.