The fastest processor your board will support is an 8370. By todays standards that is still pretty slow.
I only see used ones for just under $160 available.
For that price you could buy a new Ryzen 3600. It would run circles around that FX processor. A cheap B450 board can be had new for about 70 bucks. 16 gb of memory ddr 3000 about 45 bucks.
So basically it would really not be cost effective for the minor performance increase you would get to upgrade your board to a new/used processor.
There will also be new processors out soon that are a refresh of last years launch only a little faster and towards the end of the year Ryzen 4xxx will be out. That will drive what is currently out down in price by a little more.
You are very welcome glad you, the OP found my information HELPFUL and "just what I needed to know".
Glad to give the real correct answer.