Ok my 2 have been running side by side on 1 x Bitmain PSU and the new one is not wanting to be turned up to 750 like my old one... the hash just dropped off to zero within minuets... had to back it off to 600 the creaped it up to 675.. where its pulling 14.8 sols... could it be power that is not allowing it to be at 750?? il put it on its own PSU and see if it will run 750 ?.....
I think, each unit has slightly different OC ability, so one may run fine at 750, another may do only 700. That's my experience.
I agree there buddy.. i just found the sweet spot on the new one and its 681 @ 15.1 sols
I'm running 70 z9's . half from the first batch.
the first batch has no problem at 750
second batch defaults at "balance" which is 500 . . . you can overclock by fooling around with the firmware
The ones from the 2nd batch that allowed a 750 overclock all stopped working when overclocked at 750. as mentioned above, find your sweet spot.
I went down by 25 on all to find the sweet spot and most had their own along with fan speed. I found it best to just stay in the low 500 with zero problems and they run 24/7
hope this helps, this has been my experience so far.