I also saw this but not sure what to think of them... they're from 2016 on the market but I haven't seen anything from them I can see that they are selling antminers.... maybe they're a resell site.
I've recently started mining and I have been trying to overclock my GPU's (2 x MSI GTX 1060 6gb DDR5 [Samsung]). When mining with Claymore or any other miner I can see that the hashrates of my GPU's are not always the same and they can drop from 22.5 mh/s to about 19 mh/s at times
Is this something normal as I haven't managed to understand exactly what stability refers to. So far the computer hasn't crashed and i have run the Gpu's for at least a week on those settings
MSI afterburner:
Power: 70 Temp: 70 Core Clock: +110 Mem Clock: +800