In this instructable, I'll be presenting to you, a short, statistical, yet interesting analysis of the CPU tempertaures of the Raspberry Pi 3 i.e the Broadcom BCM 2837 that is built specifically for the new Pi 3, the Broadcom BCM2837 system-on-chip (SoC) includes four high-performance ARM Cortex-A53 processing cores running at 1.2GHz implementing the ARMv8-A 64 bit instruction set, with 32kB Level 1 and 512kB Level 2 cache memory, a VideoCore IV graphics processor, and is linked to a 1GB LPDDR2 memory module on the rear of the board.
Step 1: OVERVIEW
- Before we begin please note that I have monitored only the CPU+GPU package and the thermal output of your RasPi may vary according to the model (I have covered only the Pi 3) and the utilization of the CPU by the programs.
- Note that this is passive type of cooling as only a heatsink is used(no fans) and your temperatures might vary according to the type and/or size of the heatsink.
- I had created a temperature monitor with SD card datalogging on the Intel Edison recently, so instead of using the RasPi as a monitor, I used the Intel Edison with an LM35 Transistor as a temperature sensor while using the RasPi independently.
- I had to keep it as simple as possible, so for testing, I booted up into Raspbian and played Minecraft until the CPU temperatures settled at a maximum which, in my case, was about 20 minutes.
- Note that the "ambient temperature" in which i was working was about 32 degrees celsius.
- I have attached a heatsink to the SoC and an appropriate amount of thermal paste to it.
- In this test, i'm not pushing the Pi to its limits, as i had to do a real-world testing and so for your information I'm telling that I have noted the CPU temperatures going as high as 65-70 degrees celsius when installing Raspbian and certain high performance applications .
Step 2: TEMPERATURE ANALYSIS
- There is a slight rise in temperature while booting up and then idling sometime.
- The plot steadily goes up as the game consumes the CPU and the GPU.
- There is a steep fall in temperature after closing the game.
- The temperature rises gently as general day to day tasks are being executed.
- The temperature further drops after shutdown.
Step 3: CONCLUSION
- The model 1 and 2 of the Raspberry Pi really don't require a heatsink, but the Raspberry Pi 3 is such an improvement that you might have to consider active cooling setups while doing some serious CPU bound tasks and some of you might be surprised to hear that even the Raspberry Pi Foundation knew about this issue and so they have disabled out of the box overclocking of this model, but it can be configured via some special commands from the terminal but as soon as overclocking kicks in, the "choice" of using a cooling solution becomes an "obligation".
- I've also found that the RAM chip gets pretty hot, so i would recommend a heatsink on it too or atleast leave an air gap.
- Don't get too frustrated, the Pi 3 is really not that bad, the CPU barely touches the 40 degree mark in optimal use i.e. programming, idling,etc. and that's not just for Raspbian, i've also tried Ubuntu Mate and OSMC and I found similar results while performing normal tasks.
- In the wrap up, i'd like to say that the Raspberry Pi 3 keeps well below 40 degrees celsius in average use but soon goes above 45 as highly CPU bound tasks come into the scene, its not "obligatory" to use a heatsink with your RasPi 3 but I would "recommend" it as being on the safer side is always good.