I tested a851/a852 they sucked do not get them.
a841 are very good.
and s9 is good.
if you have a deal for the a921 and have 240 volt power there is a seller of really good psu in the marketplace.
it will do 2400 watts at plat levels.
7empest is the seller.
Noted.
I Lost a deal with the 852s.
Currently I have a deal with 821s but they're too old. But price per Tera is so cheap that makes me think of taking the deal, and whatever I save from the difference of my other deal with s9js would give me the chance to purchase the latter.
Short answer:
If you are looking for reliability, durability and stability, my order would be this (from best to worst):
Canaan>Whatsminer>Innosilicon>Bitmain (with exception of S9 and maybe S19 units).
Long answer:
I've had very few of Canaan and Whatsminer units, but they were always reliable and I never RMA-ed a single one. Everyone I knew who used these had really good "luck" with reliability compared to Bitmain.
Innosilicon is a bit different story, I've had a tad bit more of units that went through my hands or that I used personally. They were all really good and with exception of one T2T's PSU giving me blue smoke after solid 2 years of working (tho it was put through hell - it was used in miner oil a few times, then it was OC-ed to maximum "Performance+" mode during summer)
Bitmain is a complicated one... S9 were really good for me and everyone I knew personally. Out of 100 units that I had and later sold locally, they are ALL still working with OC (using exactly 1.8kW or less - depending on PSU). X11 and X15 were short series not worth mentioning. And then came X17 series, pure hell of units, I've had 75% failure rate on them. S17e was only unit that didn't break even through OC during summer. S17/S17Pro/S17+ all broke even if they were used on factory settings or underclocked. I would never recommend anyone to buy that generation of miners. X19 seems to be better, but more time has to pass so we can determine exact failure rate on them.
This is a very good information. Thank you a lot for this.
I think I accept the fact that Canaan is a better choice, and the good thing is it can save wiring Lan cable because of the array style it's using.
My only problem now is to look for another offer from the suppliers since the 852s might not be the choice now. I'm thinking since I have a very cheap rate and a good supply of power I can still mix my farm between 821s 841s and s9js if I can get my hand on a very cheap 821s.
Yesterday I had a deal for 821s @85 CAD.
if I had to choose one gear in the world it would be Whatsminer M21s but since that isn't in your list I would go with the S9.
With that being said, the Avalon 841 and the Bitmain S9 are pretty similar in terms of efficiency, so between the two, it would be a matter of cost per terahash.
My list is open since what I care is reliability + cost/Tera.
I might be open to whatsminers too.