yes, the more items you have in inventory, the less likely you are to drop that one certain item (like for example weapon or main armor), also you dont have to have no grade rings in inventory, its enough if you have any items in there (mats, scrolls, potions),even items which cannot be dropped are counted into the drop chance (just with difference that if the RNG chooses those to drop, you dont drop anything), using no grade rings has lots of cons - unlike other items you dont really use them for anything and if you drop them, the sound just scares you that you dropped something valuable as its full drop sound