Yes. Steven has told that the A841 power efficiency should be even better.
You seem to have a pretty good relationship with Canaan. I think it would be worthwhile to ask if the undervolt stuff is good for these miners or not.
Here is a copy of an email that I got from then when I asked about potential bugs in the firmware.
"e.g. there is an option to set a -2 to 1 voltage offset, this worked with the 741s, but with the 821, that option is there in the web interface, but the command that is actually used to start the miner,
*always* forces the 0 offset and ignores the value set in the web UI.
>> This option is for A741, sorry for we didn't delete this function from A821's firmware.
There is one other around the min fan speed, it defaults to 100%, what probably makes more sense is to set to that 50 by default. The outlet temperature is set to 70, where as on the 741 it was 90, because of this with the default min fan set to 100%, the fans run at 100% speed whether they need to or not.
>> We locked the fan speed in the A821 firmware since its chips cannot take high temperature.
"
You'll see my question and their response.. It is worthy of note - there are *2* voltage options on the 821, the 741 only had one. It could be they referenced the other one when they sent that I just don't know. I know it works if you change it to add to the commandline, but what I don't know is if there might be damage that could be caused by using it?
Just a thought.