F11/alt tab issue

Running into an issue with general performance when using shaders w/Iris in neoforge. When the game starts in fullscreen I'm able to run shaders mostly normally, but when I hit F11 to exit fullscreen and hit F11 again to re-enter, my FPS drops noticably, losing around 30-40 fps. This happens consistently with a large modpack and without. fresh profile with the latest versions of mods/neoforge. Tried other versions of Iris 1.8+ with the same issue.