Topic: UNDER clock Antminer S9 (Read 2408 times)

It's certainly possible to set whatever you want as the frequency but it's not easy.

Just changing the bmminer.conf file doesn't work because it has built in software that resets that particular file randomly and you'd suddenly have a screaming heat machine again if you ignore it for too long.

So you make a copy of that file say bmminer2.conf and have the autorun script call that one instead (Not really sure where it is, but should be in the /etc/rc? somewhere, I did my own custom script and renamed the run files, so I didn't actually bother to find theirs to modify it.

If you're really daring you might want to call the conf with your own custom start script and disable the existing one. Also renaming single-board-test and bmminer in the /usr/bin folder to make sure only your script calls them and they don't start by some other process. As running some of those in multiple can mess with your PIC firmware and you'd have to reset them manually (Another irritating process to be sure)

Please be careful and do so at your own risk I almost burned up an S9 figuring out how to do it properly.

I'm running two autotune R4s (@533mhz) and an autotune S9 (@425mhz) with my modifications, and they will be happily set to wherever I like them and retain those settings after reboot. Stays cool even in the hottest of the summer if you go down as low as @350mhz or so, and in the cold of winter @550mhz+ but I like to change them with each season just to keep them efficient.

If anyone wants to run a development bounty for it I'll develop the process and code changes into an easy to follow format and post it for everyone to use. Perhaps even a script that'll do it for you if the amount is worth it. Only for autotune S9s and R4s with any version of the firmware, I haven't done it with any other models.

I tried this approach of applying the 550 fixed firmware on a Couple of autofreq 13.5 units from the March '18 batch and it worked fine, leaving them at 550.
Hash dropped a ton from 14 down to 12.

You can change then change speed via the config page, 550, 600 and 650, or config file.  If you set any other value in the config file other than 550, 600 and 650 then it gets erased to "" and defaults to 600 freq, which is kind of strange for 550 fixed firmware.

Bitmain-voltage is ignored, as bmminer calculates the power based on the frequency.

Antminer-S9-all-201705031918-550M-user-Update2UBI-NF.tar.gz

I did this for a bit of a test, I don't see a significant reduction in heat \ power usage, was trying to find a sweet spot.

Are u supposed to install that firmware or did u juz do it anyway? It could have bricked the unit?

Is that fixed frequency firmware new? As in within the last 2 months? I tried to make that change on the factory firmware (something from March 2017) and the august firmware.

Did you successfully install the fixed frequency firmware first? One way to check is if your Miner Configuration page allows selection of "Search Frequency From" 550MHz.

I tried that on mine and both would go back to auto tuning the frequencies.

I managed to underclock my autotune 13TH S9 by first upgrading the firmware to the 550MHz fixed frequency firmware.

Thereafter ssh into the miner. edit /config/bmminer.conf and change

Maybe one can also undervolt by playing around with


Also one can change the directions of both the fans and the miner should reduce fan speed. Do not change the directions before underclocking though, as the miner will overheat.

Yeah, for me that was going to be too much trouble to make it worth while.

I see. Another option would be to try soundproof the room but it cost quite abit.

Not as far as I know.

I got tired of the noise and sold the damn things.

So, it cannot be done, even now?

Downclock it abit would be nice

They are currently running at 560 and I want to run them at 400 or 450.

Damn Bitmaintech.... Why let us change this stuff on older miners and not these?

never done by myself...
but i think you can do what you need just updating  the MicroSD firmware.
take a look here:
https://shop.bitmain.com/support.htm?pid=00720161126080548570Q2tDBXAH065D
you can use firmware to go at 550, 600 or 650 Mhz.
I'm sure if you run at 550 mhz, it will cool down and it will be quieter

Hmm... Might try this. The idea of these things running so hard and hot is freaking me out a bit.

One thing you could do is try my method, at your own risk. Worked smoothly with my two autotune Antminer R4's.

Originally posted in the R4 thread https://bitcointalksearch.org/topic/m.18267781

Yeah, thats what Bitmain said but there has to be a way to slow them down a bit.

If there isnt I guess I could power down one hashing board in each S9. I'd really hate to do that though.

The later models with "auto-tune" cannot be underclocked. You will need to find an early batch that still has the original firmware (batch 10 or earlier i think).

This may seem like a stupid idea but I want to under clock my S9's for the summer. They are running really hot (to the point that they stop hashing and need to be rebooted) and are really noisy. Bitmain says they cant be changed.

Thats gota be BS, yeah?

Anyone know how to slow these things down? I'll run them back up when things cool off again.