Several people are now eagerly using and testing the new SBC or single board computer from the Raspberry Pi Foundation, the Raspberry Pi Model 3, or RBPi3. Although the overall response has been of enthusiastic welcome, there are some notes of concern as to the new board running rather warm under load. Michael Larabel has run some tests to compare and show just how warm the RBPi3 can get when compared to what the RBPi2 does. Finally, we suggest some remedies for cooling down the RBPi3.
Michael has used the Phoronix Test Suite while monitoring the SoC temperature on both, the RBPi3 and RBPi2, when running the same benchmarks in the same manner for both. One important point to note is the RBPi2 was running inside its case, while the RBPi3 ran completely exposed.
The average temperature of the SoC on the RBPi3 under load was 61∞C, peaking at 82∞C. Under the same conditions, the RBPi2 (within its case), recorded an average temperature of 48.9∞C, peaking at 59∞C. That means the RBPi3 under load, operating in open air, was peaking at more than 20∞C, over its predecessor. That also means if you are planning to put the RBPi3 inside a case when operating, it might make matters worse.
Therefore, if you are planning to stress your RBPi3 routinely, you might consider the following options to keep the RBPi3 temperature down.
Wait for the Linux 4.6 kernel
According to Eric Anholt from Broadcom, the VC4 DRM driver is undergoing an update to get into the Linux 4.6 kernel merge window. This will include a significant 3D improvement in performance and a fix to the HDMI hotplug detection for the RBPi2 and RBPi3. The improvement in performance comes from the RBPi kernel DRM driver pairing with the user-space driver of the VC4 Gallium3D.
Better performance is mainly due to the pipelining, binning and rendering jobs from using xllperf or GLAMOR over OpenGL, which boosts the performance by over 20-30%. The hardware is capable of running separate threads simultaneously for binning and rendering, while OpenGl waits for them to complete before it submits the next job.
Wait for the 64-bit Raspbian
Michael has done some tests to show that there is a conclusive evidence of performance difference between using 64-bit software on supported hardware over a 32-bit operating system. Since the new RBPi3 is a 64-bit system at hardware level, the results should apply to this SBC as well.
For the test, Michael has used an Intel UX301LAA ultrabook with 8GB of RAM and 128GB SanDisk SSD. The operating system was Ubuntu 16.04 daily ISO build, in 64-bit and 32-bits version.
The average power used by the 64-bit system was 30.1W compared to 31.9W by the 32-bit system. Lowest power consumption with 64-bit build was 8.5W compared to 9.4W. The peak power consumed by the 32-bit system was higher at 54.3W compared to 49.7W by the 64-bit system.
Use a Heat Sink to Cool the RBPi3 immediately
For immediate relief, you can use the passive heatsink available that fits the RBPi2 as well as the RBPi3. At $5 from Amazon, this solution is cost-effective in addition to being immediately available. Moreover, the heatsink will drop the temperature of the SoC by almost half.
