I have a Ryzen 3 1200 with an RX560 and 2 mechanical hard drives along with the slot loading DVD drive in my Checkmate case. I haven't measured the actual power draw but I'm using a 350 watt PSU here so you definitely won't need anything higher than that for the A1222.
If you get higher rated RAM it will just clock down to the maximum supported by the motherboard. Amigakit sell 2GB sticks suitable for the A1222.
