My confid with Claymore 12.0 & Asus RX580 4GB
1 - AMD Driver 18.12.x (Newest)
2 - AMD ATI Pixel Clock Patcher atikmdag v1.4.6
3 - Claymore 12.0
4 - compute mod - on => AMD-Compute-Switcher for switch automatically to compute mode (at: https://bitcointalk.org/index.php?topic=2815803.0)
5 - Reset computer and working fine now.