Has it been flashed with a Vbios suitable for mining or running stock?
Is it the blue special edition RX590 like this one?
8 GB GDDR5, 1560 MHz GPU, 2100 MHz Memory
www.techpowerup.com
Decreasing the GPU clock while leaving the Memory clock at stock might help, or flash with another suitable Vbios:
8 GB GDDR5, 1440 MHz GPU, 2000 MHz Memory
www.techpowerup.com