As for the hanging on closing the miner mentioned above... I've seen that when under volting the cards, or trying to push the clock to high, however I do not experience hanging of the miner that often.
I have 4 of my own rigs, and have provided support on well over 25 others... and that ranges on memory through all memory types.
Very interesting you're experiencing it consistently.
I writes original vbioses and didn't touched clocks and voltages to test. And if I set straps via miner taken from miner or my own via string, after closing miner system can hang. About 50% chance of this. And when system hangs often a visual glitches stays on screen.
Myabe it because one of my cards have monitor connected. Maybe something else. I sure that it causes by returning straps back when miner closes.
Hynix MJR 8Gb memory - is a pain...