So I've had this issue for a while now. I'm not sure if it's because of my monitor (BenQ Zowie, not sure exact model but it's 144Hz) or it it's because of a driver update. It has really been making me upset recently because I go to play a game, and when I go into full screen, I get an, exact, 15 FPS cap. I've tried everything, looking everywhere. I can't seem to find the cause of it. Sometimes it happens, sometimes it doesn't. The only way for me to play at that point is to reset my PC, to see if it fixes it, or play in either borderless/windowed mode (which from what I know, doesn't utilize 144Hz)
Here are some common games it happens on:
Ark: Survival Evolved (Windows 10 Edition)
as well as a few more that I don't really play anymore.
If anyone has like a quick fix, or permanent fix for this issue, please let me know because it has been driving me crazy. Thank you!
AMD Ryzen 5 1600 AF
Radeon RX 570 RS 8GB
16GB DDR4 RAM @ 3000 Mhz
Gigabyte B450M DS3H Motherboard