Undervolting on MSI Modern 14 C13M

Undervolting a computer can significantly reduce the performance and heat generated. My undervolting of MSI Modern 14 C13M.

This laptop emits a lot of heat for how less things I do with it. On idle it sits around 50°C. If there is time where I need to compile something the temperatures go above and beyond 80°C, which is wild. Although, I understand the temp going up but for a laptop it shouldn’t go this high.

I wanted to control the heat from this laptop which lead to undervolting. I researched it well when I was doing it but only after a while did I got to understand that undervolting the CPU itself was not possible w/o bricking the system. Overclock is the other end of the spectrum which boosts the clock base speed. This in return gives maximum performance and a lot of heat. Overclocking reduces the life span of the CPU.

Controlling power limits

One effective way to control heat is to limit the power used by a computer. A low powered machine doesn’t require much energy. I tried running the below commands and for a moment everything was working normally until apps started freezing and opening apps took more time.

# Main package (usually the one that matters)
cat /sys/class/powercap/intel-rapl:0/constraint_0_power_limit_uw    # long-term (PL1)
cat /sys/class/powercap/intel-rapl:0/constraint_1_power_limit_uw    # short-term (PL2 burst)
cat /sys/class/powercap/intel-rapl:0/constraint_0_time_window_us

# Optional: energy used so far (for monitoring)
cat /sys/class/powercap/intel-rapl:0/energy_uj

# See live package power (install linux-tools if missing)
sudo pacman -S linux-tools
sudo turbostat --show PKG_Watts --interval 2 --num_iterations 5

To temporarily check if the modified values took place or not one can run below commands.

# Moderate – good balance (recommended starting point for Modern 14)
echo 28000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_0_power_limit_uw
echo 35000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_1_power_limit_uw   # short burst a bit higher

# More aggressive cooling / battery focus (very quiet, still usable)
echo 22000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_0_power_limit_uw
echo 28000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_1_power_limit_uw

# Ultra conservative (max battery, very low heat – good for office/web)
echo 18000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_0_power_limit_uw
echo 22000000 | sudo tee /sys/class/powercap/intel-rapl:0/constraint_1_power_limit_uw

All these manually running and hoping the values are correct for the system will not do. This could lead to problems. Machines can do a lot of things on their own nowadays so manually intervening seems kind of dumb.

Tools used for undervolting

Tl;dr

It didn't go as planned. Undervolting on my MSI laptop is not possible. It is locked and cannot be unlocked without bricking the system. I’m using power profiles daemon for power management.