At the heart of this change lay a new Cortex-A53 quad-core processor, boosting the device to a 64-bit architecture and offering significantly better performance vs clock speed.





Raspberry Pi 3 modelled in 6SigmaET



While the initial launch was met with a wave of positivity, within weeks of the product hitting shelves several users had begun to complain of a potential overheating issue with the new Pi. In particular, a series of posts on the Raspberry Pi subreddit raised concerns that the Pi 3’s new processor ran extremely hot when operating at full CPU load.

While the Raspberry Pi Foundation has responded to several overheating issues, including offering a firmware fix, we at 6SigmaET wanted to find out exactly why the processor was causing so many concerns – and what customers could do about it.

Identifying the problem

To explore the issue further, 6SigmaET developed a detailed thermal simulation model based on the available data of the Raspberry Pi 3. This would allow the company to investigate the component temperatures in various casing and environmental scenarios. This simulation was then calibrated against measurements from a thermal imaging camera and sensors.



Thermal Image of the Raspberry PI 3.



Both the measurements and end simulation highlighted that the Pi’s CPU naturally runs very hot at ~110ºC. While this is not hot enough for the component to cut out, it is likely to impact the longevity of the device if run continuously at this temperature.

This issue was made worse when the device was placed in a standard plastic Raspberry Pi case, which the simulation predicted will cause the processor to operate at over 120ºC – far too high for prolonged use.

