I found the bulk of my answer on Ubuntu Forums but the command to set the fan speed given was wrong. I also wrote the shell script myself (and I'm a noob), so feel free to comment how I did everything wrong, as long as you tell me how to fix it :) I added excessive comments so people who don't understand bash can get an idea of what I'm doing. This only works for 1 GPU, and will need modifications for multiple. By the way, the fan curve I have set is speed%=0.028*(degreesC^2).

Set-up

1. Run your file browser of choice as root (in my case sudo konqueror).


2. Go to /etc/X11 and allow write access to all groups (but keep the window open).


3. Open up the Nvidia X server settings window (nvidia-settings in the terminal).


4. Go to the nvidia-settings configuration.


5. Click Save Current Configuration and then click save on the pop-up window.


6. Close Nvidia Settings and run sudo nvidia-xconfig, then again with --cool-bits=4.


7. Reboot.

Script

#!/bin/bash

# Put "sleep 30" here if you run it at start-up

# to make sure this starts after the Nvidia driver does.



fan="0"

gpu="0"

echo "GPU fan controller service started."

nvidia-settings -a "[gpu:$gpu]/GPUFanControlState=1" > /dev/null

check="$(nvidia-settings -a "[fan:$fan]/GPUTargetFanSpeed=30" | tr -d '[[:space:]]')"

working="Attribute'GPUTargetFanSpeed'($(hostname):0fan:$fan)assignedvalue30."



if [[ "$check" != "$working" ]]; then

    echo "error on fan speed assignment: $check"

    echo "Should be: $working"

    exit 1

fi

while true

do

    degreesC="$(nvidia-smi -i $gpu | grep -owEe '[0-9]+C')"

    fanSpeed=$(($degreesC ** 2))

    fanSpeed=$(($fanSpeed / 50))

    if [[ $fanSpeed -gt 100 ]]

    then

        fanSpeed=100

    fi

    nvidia-settings -a "[fan:$fan]/GPUTargetFanSpeed=$fanSpeed" > /dev/null

    sleep 8

done

I probably won't be updating this in the future, as I'll be upgrading to an RX 480.