follow the link:
You can see a comparison from userbenchmark.com . ;-) Ryzen 1700 v FX - 8370
Overall is a Ryzen CPU the better choice today. Even the "little" 1700 Octa core with 3,0 Ghz is working more efficient. A high Ghz count means nothing. Ryzen can handel more threads with less use of ressources.That means, Ryzen got more power overall with 3,0 Ghz as older 4,0 Ghz CPU´s.
Your FX - 8370 is still a good CPU. For gaming more than enough. But I think in one or two years, you will get less fps on gaming.
And if you want to, you can oc Ryzen to 4,0 Ghz, if you have a propper CPU cooling.
And yes, you need a new MB with AM4 support.