I've been using sildurs vibrant shaders medium in minecraft for a while now. Using optifine for 1.16.4 and had decent fps until today. Used to get like 50-60 fps but now I get like 20 or even lower. Haven't changed any settings. Restarted the game and my pc multiple times. Realistically I should be able to run it like I did before or even higher. I got a rx 5700, ryzen 2700x, 2x8gb 3200 mhz Ram.