I'm running a Raspberry Pi at home for various tasks and access it remotely using SSH for all maintanence tasks. This means that the HDMI control in the Pi is unused and hence can be switched off for maybe not better performance, but at least for a lower working temperature.
When logged in, you can switch the HDMI off by running
However, this will reset at boot time. So one way to handle this is to simply add the command to the boot scripts.
I did it the quick way by adding the command to the boot sequence:
### BEGIN INIT INFO
# Provides: customboot
# Required-Start: networking
# Required-Stop: networking
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Custom boot commands
# Description: Custom boot commands
### END INIT INFO
echo "Turning off tvservice"
Then add permissions and add the script to the boot sequence
sudo chmod +x /etc/init.d/customboot.sh
sudo update-rc.d customboot.sh defaults
By doing this, I lowered the idle temperature of my Pi with about two degrees C: