A:AnswerAccording to ASRock's Website, it should be able to handle Ryzen 3 chips, provided the BIOS have been updated. If they have not yet, you'll need to do that first before the chip will be recognized. Newly bought boards should be fully updated, provided they haven't been sitting in a warehouse for too long, but if not, use the boards 'instant flash' feature to update.
A:AnswerDepends on your cases airflow, ambient temperature in the room you’re in, quite a few different factors. Probably not easy to give you a solid answer.
A:AnswerSize? You mean the CPU socket? They are either AMD or Intel. That's it, any processor you buy from any reputable seller will fit it is all universal. Where it will differ is the motherboard, AMD or Intel. For that question, google your board or the site that you are buying it from to see if it's an AMD or Intel board. CPU sizes are all the same. This will fit on an AMD board.