Improving the Cooling on the Raspberry Pi 400

Runs steady at 2.2GHZ with the modified cooling keeping it under 50C at all times.

You'll need a guitar pick or spudger, some good thermal grease, 2mm of thermal pad, a phillips screwdriver and a fine file.

Using the pick or spudger go around the perminiter of the unit where the plastic halves meet. It will pop open pretty easy but be careful of the keyboard cable. Once it's open lift the black plastic bar to release the keyboard cable. This will leave it in half with the large aluminum heatsink and the 4 screws that hold it. Unscrew those and lift it away. It's held to the CPU with double stick tape. We will need to remove that and clean the surfaces too.

Clean the CPU and RAM chip under it with alcohol carefully. When cleaned gently file about 0.5mm off the two screw standoffs nearest the CPU to lower the cooler to the chip directly. I added my CPU grease and screwed in the heat sink to test contact. I added the 2mm thermal pad to cool the RAM chip as well. Here I also added two 0.5mm thermal pads between the keyboard and heatsink just because.

Carefully assemble the unit and plug the keyboard cable back in then close the latch and snap the case together by pressing around the edge.

Now you can set your overclock:

#Overclock

over_voltage=6

arm_freq=2200

gpu_freq=750

gpu_mem=256

This is how mine is set in config.txt in the boot partition. My unit has a MSATA SSD in a USB 3.1 case to run off of on Raspberry Pi OS Bullseye.