Is 500w PSU enough for RX 580?

A quality of 500 watts is enough for an RX 580, but it is the minimum recommended level as a Tier 5 PSU. If you already have all these PSU and an RX 580, it will do the trick. Yet, it is a good idea to have some extra capacity in a power supply, so you should replace it down the road when you have the opportunity to upgrade to a better PSU.