Is the game that poorly optimized for AMD cards?

7f75c5f9-4016-4a15-b4cf-c0ac1287dd2d-image.png I've undervolted my GPU from 1150mV to 1100, while keeping stock frequencies.

Today, during a Mining Base run, my GPU turned itself off (no signal on my monitors). Music still ran and whatnot. Had to induce a shutdown via power button. I had to change the voltage because the card runs hot; 83°C. With the voltage turned down, I got it to 79°C. It still does not tell me why it just randomly shut itself down while playing the game. Other games, like Borderlands 3, at ultra settings, with an unlocked frame rate, never caused the card to turn off.

How is a 2012 game doing this to a 2019 card?!? ASRock Phantom Gaming U RX 590 8G OC

I suggest updating your graphics card drivers. I personally have not seen any problems with the interaction between Phantasy Star Online 2 and my amd graphics cards.