"The Radeon RX 580 will live a complicated life. One side of the fence will forever see it as only the rebrand of the Polaris-based RX 480 cards released in the middle of 2016 while another will see it as a very mild upgrade and replacement for a series of cards that got AMD and the Radeon brand back into the competitive cycle. In many ways, both are correct. Don’t be confused by the numbering scheme – this could have very easily been called the “Radeon RX 485” and offered the same differentiation factors and performance improvements and we would have all been satisfied. But the naming decision aside, the RX 580 (and the rest of the 500-series) will offer users slightly better performance than the RX 400-series equivalent, at the same price points. And because AMD isn’t trying to pull a fast one on any of us by telling us how great and amazing the RX 580 is compared to the RX 480, I’ll give them a pass. If you were looking at the RX 480 yesterday, you should be looking at the RX 580 today."
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips