Cat9.12 crossfireX eyefinity Hotfix was the last and only driver that properly supported 3 monitor eyefinity with xfire enabled. GPU42ATICatalyst9.12Hotfix
It says to use this driver in the Cat10.2 release notes. They havn't said in Cat10.3 if the issues had been resolved or not.
Also, run a complete memtest86+ v4 on your memory to verify full stability. Atipmdag.sys is a memory manager and Driver_IRQL_NOT_LESS_OR_EQUAL errors can occur with upper corrupt memory.