The results are in:
I’ve been very busy with different projects, and one of them requires a custom enclosure. So I thought it would be an excellent excuse to learn Fusion 360. When the Raspberry Pi 3 came out, I did some overclocking experiments. But I settled with just passive cooling with some small aluminum heatsinks. But after seeing some tests done with a more massive copper heatsink combined with a cooling fan, I decided that I wanted to build a case with a silent fan with enough room for a large heatsink. I need it for my NTP server at ntp.jacken.se to get better performance.
So time to dig into Fusion 360. I like the interface and building the box was a lot of fun. There’s a lot of great tutorials on Youtube on how to get started, and Autodesk has a lot of suitable material as well. I built everything with parametric variables, so I can quickly change things like wall thickness, height, etc. and everything automatically adjusts accordingly.
I’ve tried to plan the best airflow through the box. The fan sucks in air through the vents on the side and from the bottom of the case, where I have put an air intake for cooling the RAM chip. I’m going to experiment with the raisers for the PCB so I can put a heatsink on the RAM as well. The other opening is on the side to funnel fresh air over the copper heatsink and have the hot air exiting at the top. I’m going to try to find a 5-volt fan, but otherwise, I’ll just build a small boost converter, taking 5 volts from the Raspberry Pi and convert it to 12 volts. It wouldn’t be too much of a problem to use PWM to regulate the fan speed as well. Then it can adjust the fan speed as needed.
Thankfully I have a friend at my old workplace, where they have an UltiMaker 2 3D printer, so I’ll have a prototype in a couple of days. It’s going to be interesting to see if the clearances are correct from the published drawings of the Raspberry Pi 3.
If everything fits, it’s time to start finding the most massive copper heatsink I can install and begin to push the envelope of overclocking on the Raspberry Pi 3. But even if I am not able to overclock more, at least the CPU will run around 50˚C instead of 70-75˚C.
Update: Got a prototype printed on an UltiMaker 2. Yay!
I put my Raspberry Pi 3 NTP server in my new case and adding an eBay boost converter to get 12 Volts from the 5 Volt pin on the Raspberry Pi 3 and adding a Gelid Solutions Silent 5 fan. I ran sysbench five times in a row while checking the temperature and when overclocking to 1.4 GHz, it hovered around 68-69˚C and stayed there when the processor was running at full tilt. I lowered the voltage to the fan to around 7 Volts, so It runs silent, and it still worked with the anemic little aluminum heatsink I have. It’s now running dead silent and stable at 1400 Mhz. As you can see from the statistics screenshot, the machine when overclocked to 1350 Mhz used to hover around 54˚C, it now stays around 42˚C when running 1.4 GHz and the memory running at 550 Mhz. I call that a success.