I am almost certain that I have narrowed this down to Shader Caching (I could be dead wrong). Every once in a while when I log into the game my FPS is 1/4 of its max amount, with tons of fps drops. The longer I let the game sit the fps will go up to 1/2 max frame rate, 3/4 max frame rate and then stabilize. Sometimes this happens quickly, sometimes it takes up to 2 matches before it works itself out.
Why I think this? After tons of researching, I found an obscure thread that said to clear my AMD shader cache and after I did, this problem went away for a good while. I learned though when I log in and this issue is there, to just wait in the training area for it to go away.
This is an issue though that I should not be having or dealing with in this way.
AMD cards, especially the 6000 series and beyond, build the shader cache when you login. That’s how the cards and their drivers work. Some players hang in the training area to let everything load before they go into matches. I agree it’s inconvenient, but this is an AMD issue that they are aware of and haven’t changed.
I have the same problem with a RX6600 but it only happens in Overwatch, I never played a game that makes shaders while I’m playing, every game does it on a loading screen when you start it, so its not an AMD issue but an Overwatch issue, you should at least warning the player that the game is doing shaders.
Drivers are built to work for games, not the other way around. In short, it is an AMD issue because they built the driver to work like that for Overwatch. Maybe none of the other games you play experience it, but lots of other titles do. The AMD forum is littered with complaints.