Antminer Z9/Z9 mini 13.5W/Ksol Undervolted

[FrozenChip]

After many many hours of investigation i finally managed to undervolt a Z9 mini.
Power usage can be as low as 13.5Watt/Ksol at the wall(power meter) with a platinum power supply and this was a z9 mini batch 2, so all other batches should perform slightly better.
I get 10Ksol with only 138W, which is almost 50% less power comparing to official specs.
Undervolted Z9 mini, can be made silent, with 2 x under 20db fans and a fan simulator
Same performance/watt can be reached on Z9

More details of my tests below

Stock performance

Frequency	Watt	Ksol	W/Ksol
700	363	15.3	23.7
600	311	13.1	23.7
500	259	11.5	22.5
400	210	9.3	22.6

Undervolted

Frequency	Watt	Ksol	W/Ksol
700	321	15.2	21.1
600	237	13.0	18.2
500	173	11.5	15.0
400	126	9.2	13.7

I'm not sharing any how to details because my solution, at this stage, requires additional tools and is too difficult
The software solution will be much better if it can reach the efficiency above.

I've tried playing with the Antminer L3+ solution
https://bitcointalk.org/index.php?topic=3546316.0

but there is no "/dev/i2c-0" file on Z9 mini

Anyone with more knowledge, please share your thoughts on how to get access to those chips through i2c in a similar way it was done for L3+

[FrozenChip]

And very important benefit from voltage control
If i slightly undervolt, i can then overclock to higher frequencies. It has a max amp/power limitation.
My batch 2 could never hold stable anything above 650Mhz. I can do 737Mhz now.
Batch 1 owners should be able to go  as high as 800Mhz.

[efudd]

And very important benefit from voltage control
If i slightly undervolt, i can then overclock to higher frequencies. It has a max amp/power limitation.
My batch 2 could never hold stable anything above 650Mhz. I can do 737Mhz now.
Batch 1 owners should be able to go  as high as 800Mhz.

An important note is more important than frequency is your share rate -- which is more important than hash rate.

This is not to dismiss your statement on overclocking, as more should be "Better" -- but I agree that their voltage/frequency curves may not be ideal.

As I told you in PM, bitmain has attempted to hide the software interfaces for I2C, which means communications with the PIC and voltage controller, as well as fans, are obscured at a minimum.

I have some ideas and some pointers on breaking down that wall, but I have to lock down some other components of my work before I move to this more esoteric (yet valuable) work.

Thank you,

Jason

[fanatic26_]

An important note is more important than frequency is your share rate -- which is more important than hash rate.

Share rates depending on difficulty and pool settings and can be different for the same coin depending on where you are mining. This makes the share rate a poor metric except for comparing machines connected to an identical pool.

[efudd]

An important note is more important than frequency is your share rate -- which is more important than hash rate.

Share rates depending on difficulty and pool settings and can be different for the same coin depending on where you are mining. This makes the share rate a poor metric except for comparing machines connected to an identical pool.

Share rate is what you get paid on. And yes, it varies by luck and such... within a pool, share rate is how I'd measure the effectiveness of a modification... so I stand by my statement.

Jason

[786sam]

Do you find it stable whilst undervolting? Care to share any results bro?

[Multikevin97]

Hi there!
I know it has been a long time but I managed to get the same (if not better)efficiency results as mentioned and they are stable.
If there is interrest I will do a tutorial as it requires a simple hardware mod.
Kind regards,
Kev

[Hazzzs]

I'd be interested, even if it's just a quick runthrough reply here.

[TehnoMining]

Hi there! I know it has been a long time but I managed to get the same (if not better)efficiency results as mentioned and they are stable. If there is interrest I will do a tutorial as it requires a simple hardware mod. Kind regards, Kev

Hello Kevin! I and some more forum members want to know about hardware mod for undervolting Z9 Mini ASIC miner