Did you upgrade drivers? If so try uninstalling them using DDU and then install. You can do the same thing and use a prior driver that worked. Try running one card at a time to see if one card OC's. Check your Crossfire cable. Do games run at normal speed or at all?
Alternatively, it's time to slide up to something like the RX580,480, R9390 type thing. Used, an R9390X go for like $120-130 in good shape. Not to knock your hardware but it's "end of life" stuff with zero support. So is the R9390 but I know for a fact those cards are still no slouch. A single GPU with 8GB DDR5 will work better than those 2.
Now if you really want an upgrade, go with the RX 5600 XT, for under $280, they kick some butt. Assuming your CPU is as old as the cards, you don't need to spend a lot for a good card or even the newest to get good 1080p frames. 4K, well to get 60 FPS, I'm sure you know would be an undertaking.