I actually do watch memory errors, thats why me and you have worse results than some scammers 
I have 13.8-13-9 with the same card as you
I have 13.8-13-9 with the same card as you
So, I'll have to fight again with Hynix to get close to your 13.8 Mh/s.
It was actually about 14.4 until recently, only thing that changed meantime is new epoch,
but since my micron based Gigabyte took almost no drop, I'm a bit confused here