Did you buy them from bitmain or on ebay? If you got them directly from Bitmain i would call them. Kinda odd you bought 2 from batch six and they dont look the same.
JT
I bought from
https://bitmaintech.com/product.htmthey really look different, one has curved heatsinks - the bad one (just like this
http://img.youtube.com/vi/VOyrCut0y30/0.jpg), other has straight - the good one. If you are still interested, by the end of the week I will take pics for comparison, I have decided to run them until end of the week without restarts (so will not remove cover - this will require downtime) and see what AVG I get. After I took them down for testing yesterday they both had good 3 hour AVG during night (890 for both), and now it is 5% down as usual for one of the units and going lower (now it is 865), I have a feeling it will stay there and go lower - to 840. I will remind in pm when I have full analysis to those who were interested about this.
EDIT: "3 hour AVG for two miners not 865, but 840 already - I think this is what it will stay until I reboot on weekend, so 5% drop for both units, but actually only one is losing speed, which makes it around 10% for that unit"I only cleaned heatsink on the bad one, it was covered in thick dust layer at the front side (probably the good one is the same, but aint touching it while it runs good), it runs more quiet now after cleaning, but the hashrate AVG behavior did not change.
I already contacted bitmain, they suggested: firmware update (which I did not do, because from what I saw it brings only features I do not need and from what I read for some people it got worse after update), and testing hashboards one by one by disconnecting them which I did not try also.
I agree there is no point in sending back if it is 10% slower than it should be (or rather 5%, because bitmain states that -5% is ok). I was hoping that restarts are good idea, but it seems not - losing shares?
I also tightened screws on heatsinks of the bad unint as one of posters on this page recommended.
So lets wait until I post analysis of running without interruptions and thank you for the interest, did not expect this, my initial idea was just to ask if the restarts is a good idea