If I use any overlay (Heartharena, Hearthstone Deck Tracker, etc.) the FPS drops and the game starts stuttering. Issue goes away instantly after closing the overlay app. No issue before switching to windows 11. I have completed removed and reinstalled my graphics driver, disabled AV and reinstalled win11. Issue persists.
EDIT: Also, this only happens with the game in full screen mode, issue vanishes in windowed mode, but obviously this is far from ideal with trying to play, let alone with an overlay.
I have this same problem. It happens not only with overlays that affect hearthstone, but other overlays like steam (friends coming online or other alerts). I have a feeling it might be something with windows 11 because my old windows 10 install didn’t do this and even a fresh install of windows 11 doesn’t fix the issue. It would be nice to get more traffic on this issue because I guarantee that more people have this issue than are willing to post about it.