hi
my rx580 8gb stop mining ETC at #379 epoch (4GB DAG size) in win10 & PhoenixMiner 5.1c
but still work ETH at #368 epoch.
my driver is Crimson Beta for Blockchain.
i dont have any problem in linux but some rigs work in win10.
any suggestion?
 

Good drivers. These are versions from 18.12.1.1 to 19.7.5 (inclusive), and from 19.12.2 to 20.8.1 (inclusive). These will allow you to mine until DAG epoch 372-373 and won't need restart of PhoenixMiner on each DAG epoch change.
Not so good drivers. These are versions 18.1.1 to 18.10.1 (inclusive), and from 19.8.1 to 19.12.1 (inclusive). This will allow you to mine until DAG epoch 365-366 and will require restart of PhoenixMiner on each DAG epoch change (for these drivers this will be preformed automatically unless you have added -dagrestart 0 command-line option to explicitly disable the auto-restart).