Unfortunately I also have a bad experience with the Sapphire RX480 8 GB Nitro models. Out of 24 of those cards, 4 pieces died for me. I maintained them regularly, blew them with a compressor, put the best thermal paste "Thermal grizzly kryonaut", I have a very high quality and reliable power supply. I am very disappointed. So I went back to MSI again. Now I only use the MSI 5700XT Gaming-X series graphics cards . I used to have several MSI 7950 Twin Frozr IIIs and have been mining with them for years. None of them ever died. Fans did go, but graphics cards never did.
And what is the reason? These video cards have a 3-year warranty. Did they break in the first 3 years or after?
Various models broke down for me, but I even got a profit from this, because the store returned the money to me.
I have a lot of 5600 ХТ Saphir and these GPUs are the best.