Raspberry Pi 3 B+
Another slice of Pi to tuck into, and one that is incrementally better than the last.
Another Raspberry Pi! Will this be the fabled Raspberry Pi 4 offering USB 3.0, SATA, GTX 1080 GPU, octa-core CPU and 16GB of DDR4 RAM?
So let’s first address the obvious questions. No, this isn’t the Raspberry Pi 4 and no, it has none of those features. Rather, the Raspberry Pi 3+ is an incremental improvement of the Pi 3 B that gives us a little more power, and much better connectivity. This is not the first B+ board — that was the original B+ released in 2014 and saw the first board design morph into what has become the de facto standard board layout, often emulated, but so far unbeaten by its competitors.
INCREMENTAL UPDATE
Let’s start with System on a Chip (SOC), which is a BCM2837B0 containing the CPU. Just like the Pi 3, we have an ARM Cortex A53 64-bit CPU, but now running at 1.4GHz, which is an increase of 200MHz over the Pi 3. It’s not a massive increase, but it helps to make Raspbian run a little bit smoother. In general operation Raspbian felt more responsive and it was a genuine pleasure to use, so that extra power really did the trick.
RAM remains the same at 1GB. That’s enough for most Pi power users, but it would have been nice to see 2GB of RAM which is rapidly becoming the norm thanks to boards such as Asus Tinkerboard. We ran a sysbench test, computing prime numbers up to 10,000 using all four cores of the CPU. The Pi 3 B+ did this in 36.583 seconds, versus 45.7046 for the original Pi 3. A profound result — that’s nearly 20 per cent quicker than the original Pi 3!
IMPROVED NETWORKING
With the Pi 3 in 2016 we saw the inclusion of onboard Wi-Fi and Bluetooth, and this has been further improved for the Pi3 + with Wi-Fi now offering 5GHz 802.11ac. This has a much higher throughput — theoretically up to 1.3Gbits per second — but in tests we found it to be 74Mbits/sec (9.25MB/s) versus the standard 802.11n speed of 47.8Mbits/sec (5.875MB/s).
Taking a feature from the Pi Zero W we find that the wireless antenna is the same design, a licensed feature from Proant AB. There’s no connection for an external antenna. This new 5GHz Wi-Fi option works remarkably well and in our tests we were able to watch a 1,080p YouTube video with only a slight amount of buffering when it started to play.
Another improvement is with Ethernet. On the previous models of Pi we have seen a LAN9512 and LAN9514 controller chip that offered USB 2.0 ports and an Ethernet connection. For the Pi 3 B+ we see the new LAN7515 providing Gigabit Ethernet over a USB 2.0 interface. So with this new chip running the Ethernet at 325Mbits/sec (40.6MB/s) we see a vast improvement — over three times the performance — when compared to the previous Pi 3, which had a bandwidth of 94.3Mbits/sec (11.78MB/s).
When compared to the Asus Tinkerboard, which uses an RTL8211E chip for true Gigabit connectivity (in tests we recorded 939Mbits/s, which is 117.375MB/s), the Pi 3 B+ is still slow. However, for general operation and use as a home file server it’s a welcome increase in performance that offers plenty of bandwidth for streaming files at truly reasonable speeds. Bluetooth is also improved to BLE 4.2.
POWER OVER ETHERNET
The now standard 40-pin GPIO (General Purpose Input Output) remains the same, ensuring compatibility with the many add-on boards available. We tested the
GPIO using the traditional RPi.GPIO Python library as well as GPIO Zero and found that all was well, including the use of add-on boards.
Just next to the GPIO pins are four extra pins labelled PoE (Power other Ethernet), which enables the Pi 3+ to be powered and communicate using one cable. This will be via a future PoE HAT. But there arises one little problem. The placement of the PoE pins means that they’ll be obscured by any HAT specification boards placed on the GPIO. We speculate that the new PoE HAT will have a passthrough GPIO connection, but at time of writing there’s no information. The PoE pins introduce the possibility of some boards making direct contact with the pins, which risks shorting components on the underside of boards. We advise checking your clearance before applying the power.
LEGACY PORTS
The Pi 3 B+ has the same ports as those found on the Pi 3 (HDMI, an official camera/display and a combined audio/video jack) No changes are made to the USB, either with four USB 2.0 ports offering enough connectivity for most users. Power is provided via the micro USB port and the official 5V 2.5A power supply is recommended.
At idle the Pi 3 B+ can pull around 530mA, but when watching a YouTube video in fullscreen this went up to 1A and we saw the dreaded lightning bolt icon on the desktop, indicating that out power source was inadequate. So we swapped to the official power supply, which thankfully solved the issue.
BETTER THERMALS
There’s no denying that the Pi 3 could run a little hot. In fact we ran ours under stress, playing a YouTube video, flying around in
Minecraft and a stress test computing prime numbers with sysbench, and the device reached 81.1°C. But with the Pi 3 B+ the highest temp we found was 67.1°C. All down to a new thermal cap to help dissipate heat and makes it ideal for use as a home media player, which is typically placed inside a case.
DESKTOP REPLACEMENT
For some users the Raspberry Pi, rather than being a platform for making/hacking, has been seen as a low-cost alternative, general-purpose computer. In previous versions this was possible if a few compromises were made, chiefly web browsing. But since Chromium was chosen as the default browser, we’ve seen an increase in processing power and now with the wired/wireless connectivity improvements, especially in the Pi 3, we now have a Raspberry Pi that could be quite easily used as a replacement to an older computer. Not forgetting, of course, the added bonus that it runs quietly and uses far less power than a laptop or desktop computer.
The Raspberry Pi 3 B+ may not be the ‘Raspberry Pi 4’ but it was never really intended to be. Instead, it’s an incremental update that provides users with refinements to the existing package. The improved CPU power is a welcome boost, but the biggest improvement is networking. Providing something better than the 100Mbps found in the older models via Gigabit over USB2 will help users eager to build networked devices, and for those with 802.11ac routers the 5GHz Wi-Fi is an excellent compromise of speed and portability.
The Raspberry Pi 3 B+ deserves a lot of love. It brings new features and improvements while remaining true to its roots. The GPIO is the same as all previous models (ironically the original B+ onwards), but do take into consideration the PoE pins and make sure that your board isn’t touching them.
The price of the Raspberry Pi 3 B+ mirrors that of the original Pi 3, so if you’re new to the Pi then this is the model to purchase. Existing Pi 3 owners may need to justify the purchase, though.
In sum, this is a great board; a worthy successor to the Pi 3, and a step along the path to what we hope to see in the Raspberry Pi 4.