I'd sure hate to see someone waste money. So few games have been optimized for crossfire in the last few years. And your mileage will really vary with the older titles that did with current drivers. I strongly suggest a stronger single GPU solution. I have a RX 580 and find it is very good up to 1440p 60hz.
Unless you are getting that FX for very little money. I agree with the others. You can get Ryzen or Intel offerings for similar pricing that are just going to be so much better and modern motherboard features too.