mietzen/m720q_setup.md

## m720q_setup.md

      
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              m720q_setup.md
            
          
    m720q Setup with an i7-8700 65W

I had trouble getting my i7-8700 65W to work in my m720q with a 65W PSU.
It was working fine in Windows, but was throttling down first to 20 Watt, then to 15, 10, and finally to 7 Watt, which resulted in a maximum clock speed of 800 MHz.
The main problem seems to be a mix of crappy firmware settings from Lenovo/Intel (Reddit Post)
and the weak power supply.
To fix this problem, we have to install some tools, and for them to work, you have to make sure that secure boot is OFF; otherwise, the kernel doesn't allow you to set the CPU power limits. The easiest way is to install in legacy mode; therefore, you need to disable secure boot and enable CSM in the BIOS, select legacy boot preferred.
After we made sure that secure boot is OFF, we need intel-undervolt, which enables us to set the power limits.
All commands are run as root.
Enter a root Shell with: sudo -i
apt update
apt install git build-essential pkg-config powertop s-tui stress-ng -y
cd /opt
git clone https://github.com/kitsunyan/intel-undervolt.git
cd intel-undervolt
./config && make && make install
cd ..
rm -rf intel-undervolt
Then we need to configure intel-undervolt:
cat <<EOF > /etc/intel-undervolt.conf
power package 35/10 35/81920
EOF

It is very important NOT to raise the power limit above 35 Watt, neither PL1 nor PL2. It will result in a very short burst of ~38 Watt of pkg power consumption; afterward, the CPU goes into some kind of save state and throttles to 7 Watt!

The duration of PL1 and PL2 doesn't seem to be applied/working. Once you created the config, apply it.
intel-undervolt apply

You should now test your settings with s-tui if the package power is ~35 Watt, everything is fine.

Make it permanent:

I noticed that the service somehow needs some cool down after the system is started, so I added a delay of 30 seconds.
cat <<EOF > /etc/systemd/system/intel-undervolt.service
[Unit]
Description=Intel Undervolt Service
After=multi-user.target suspend.target hibernate.target hybrid-sleep.target

[Service]
Type=oneshot
ExecStartPre=/bin/sleep 30
ExecStart=/usr/bin/intel-undervolt apply

[Install]
WantedBy=multi-user.target suspend.target hibernate.target hybrid-sleep.target
EOF

Afterwards enable the service:
systemctl enable intel-undervolt.service

Reboot and test again with s-tui.
Optinal Undervolt:

Be careful undervolting might have effects on your system stability! Always test the undervolt before activating the service or you may end up with a unusable OS!
To activate undervolting, we have to edit an EFI variable since undervolting is locked. Therefore, create a ventoy stick and put the following .efi binary on it:
https://github.com/datasone/grub-mod-setup_var/releases/download/1.4/modGRUBShell.efi
Boot into modGRUBShell via ventoy and typ in the following commands
setup_var 0x7BD 0x00


and then:
reboot

Remove the stick and boot back into linux, now add the undervolt to your config
cat <<EOF >> /etc/intel-undervolt.conf
undervolt 0 'CPU' -75
undervolt 1 'GPU' 0
undervolt 2 'CPU Cache' 0
undervolt 3 'System Agent' 0
undervolt 4 'Analog I/O' 0
EOF

and apply it:
intel-undervolt apply

Further power tuning:

You can further power tune your system by running powertop:
powertop --auto-tune

And setting the cpu govenor to powersave instead of performance:
cpupower frequency-set -g powersave


Your system should now idle at 5-7 Watt and underload it should be consume around 55 Watt
Sources:


https://github.com/kitsunyan/intel-undervolt
https://wiki.archlinux.org/title/CPU_frequency_scaling
https://www.reddit.com/r/thinkpad/comments/etiotf/there_is_still_no_official_fix_for_the_linux/
https://forums.servethehome.com/index.php?threads/lenovo-thinkcentre-thinkstation-tiny-project-tinyminimicro-reference-thread.34925/post-362574
https://github.com/datasone/grub-mod-setup_var