When i launch BoTW on cemu it goes on a smooth 45 fps, but after 30-60 mins my fps drops to 15-20. The only way to make the game playable is to reboot the game every 30 mins. I followed everything BSoD Gaming (youtube channel) showed in his BoTW full setup vid.
My specs are:
8GB Ram
NVIDIA GeForce GTX 1050
Intel i5 7400 (quad)