When my PC turns on, my Vega GPU cannot go under any major load, or the card will shut off (the PC remains on). Also, after a shutdown, it won't stay on for very long, and will shut off after a few minutes of use. I have to leave the system unplugged for several hours for the card to be useful for web browsing and YouTube videos again, but still no games. What is going on with the card? I have already tried different power supplies.