The problem is with Windows 10 itself,it always had a lot of problems by mining with 12 GPU-s,don't know anyone who has done so for a long time without crashing.A friend of mine though could mine really well with up to 10 GPU-s in such board with Windows 10 and once the 11th and 12th were added it immediately started creating problems,the cards were RX 580 at that time.He tried a lot of things but in the end he switched to HiveOS and his problems immediately disappeared after that.So your best solution would be to migrate to a Linux based OS like the HiveOS.