There are a few key things that can cause this behavior, its almost always a temperature of power related issue.
- Most graphics cards GPU runs in the 75-85' C range, however it can run up to 90'c safely. If you have a newer graphics card that also has a Junction/Hotspot temperature reading this will usually run in the 85-95' Celsius range, but some models may run into the 100's Celsius safely. Most graphics cards will invoke a system shut down if getting into the 100's Celcius on the main GPU temperature reading. You can use the AMD settings to monitor temperatures, or something like GPU-Z https://www.techpowerup.com/gpuz/ .
- Check your video cards fans, especially if you owned the card for a few years, check to make sure the heatsink is not clogged with dust and that the fans are still spinning freely without resistance.
- Be sure to check the CPU temperature as well. Like GPU's they have a thermal shutdown function, the temperature will vary by CPU, but generally its in the 70 to 100 degrees Celsius range.
- This is a bit more difficult the troubleshoot, usually requires an alternate power supply. If you power supply comes with alternate PCI-E power connectors you can try those and see if the system stabilizes. But if your temperatures on both the CPU and GPU are looking good this is your most likely culprit.
If you feel you graphics card is the cause after troubleshooting, please register your graphics card and file a support ticket at https://support.xfxproducts.com/ in the ticket describe the issue in detail and also provide what troubleshooting steps you have taken.