This's Crimson Relive : http://support.amd.com/en-us/kb-articles/Pages/Radeon-Software-Crimson-ReLive-Edition-Beta-for-Blockchain-Compute-Release-Notes.aspx. will fix Dag epoch.

I didn't have experience with the last version of The PBE, so far as I know and based on experience hynix and samsung chips stable with copying 1750 to above. so I suggest to using 1.6.2. you can patch driver signature using atikmdag patcher.