I have power color RX 580 8 GB OC, it's working fine honestly. depending on how long you had your GPU, you might be do for a good clearing of the dust or even a repaste (yes that's a thing, the old paste can get pretty crusty) Also depending on your GPU, you might want to look it up on google or in specific forums if possible to see if there are any known issues and fixes.

Check your fan curve to see if the fans are tuning to a high enough RPM as well.