2. What is the HW %
0 (zero). Last try it got a an occasional HW error, but they were minor. One of the six units got a bogged down in HW errors, but then performed well when I dropped the frequency to 268.
I assume that when your avg hash-rate falls you restart(ed) immediately, so seeing you have no HW errors, could you let it run for at least an hour after that and see whether you get any HW errors and / or x's on the chips?
I also noticed that the 5s hash-rate flactuates whenever a new block is started / a block is about to end, but soon builds up, so that may be something you have to bear in mind (assuming your hash-rate recovers!).