I have not been able to underclock my T9+ with the supposed settings that were suggested here but playing around with the ideas from here I found a solution that I wanted to post / share.
So the problem was that that my miner also already had autotuning available and changing
"bitmain-freq": "some_value" would be ignored after rebooting.
So first I recognized using
top that there was a process
/usr/bin/bmminer --version-file /usr/bin/compile_time --api-listen --default-config /config/bmminer.conf running.
Thus I checked
/usr/bin/bmminer --help to recognize that there is an option
--fixed-freq Set bitmain miner use fixed freq which probably could also be set in
/config/bmminer.conf.
Thus I added the line
"fixed-freq":true, to the
bmminer.conf so that in total it looked like that:
{
"pools" : [
{
"url" : "",
"user" : "",
"pass" : ""
}
]
,
"api-listen" : true,
"api-network" : true,
"api-groups" : "A:stats:pools:devs:summary:version",
"api-allow" : "A:0/0,W:*",
"fixed-freq" : true,
"bitmain-fan-ctrl": true,
"bitmain-fan-pwm": "50",
"bitmain-use-vil" : true,
"bitmain-freq" : "300",
"bitmain-voltage" : "0706",
"multi-version" : "1"
}
In this way I was able to underclock the miner and tune down the fan. actually the PSU is now more noise as it's fan cannot be regulated by the software (what a pitty because it still produces 50db).
running the following firmware:
Miner Type Antminer T9+
Hostname miner2
Model GNU/Linux
Hardware Version 16.0.1.3
Kernel Version Linux 3.14.0-xilinx-ge8a2f71-dirty #82 SMP PREEMPT Tue May 16 19:49:53 CST 2017
File System Version Wed Nov 15 17:18:06 CST 2017
Logic Version T9+_V2.40
BMminer Version 2.0.0
