Raspberry Pi 4
Les Pounder loves a surprise and a Raspberry Pi –so when the Pi 4 was released, he was over the moon!
Surprise! Mid-year is not a traditional release date for a Raspberry Pi. In fact, this new version of the Pi breaks a few traditions. Firstly, it was released far earlier than predicted due to the BCM2711 System on Chip (SoC) being ready for production some nine to 12 months early. Secondly, there’s the price: there is now not just one price for a Raspberry Pi Model B, but three. At $59.95, the basic model comes with 1GB of RAM; for $77.95 there is a 2GB model; and for $94.95 there is a 4GB model. For this review we have chosen to look at the 1GB model as we can directly compare it to previous models of Pi.
No matter the version of Pi 4, all come with a 1.5GHz 64-bit quad-core Arm Cortex-A72 CPU (Arm v8, BCM2711B0) and all of the RAM is now LPDDR4, giving us a much-needed boost in performance. GPU duties are handled by the new VideoCore VI which supports OpenGL ES3.0 and provides another handy
boost in performance.
If you are a keen maker/ hacker then fear not, as the 40-pin GPIO is present and fully compatible with HAT and pHAT boards. But in a change to previous GPIO configurations, the GPIO of the Pi4 offers four each of I2C, UART and SPI interfaces, enabling more compatible devices to be connected – all by changing the device tree overlay on boot.
For network connectivity, we are truly spoilt. While the Pi 4 retains the excellent 2.4GHz and 5GHz Wi-Fi from the 3B+, we finally have true gigabit Ethernet on a Raspberry Pi thanks to the BCM54213 Ethernet chip, which provided a stonking 931Mbits/sec in our test – around three times faster than the 3B+. No more Ethernet through USB!
Talking of USB, the Pi 4 has four USB ports – two of which are USB 2.0 and the others USB 3.0, which have their own chip that connects to the SoC via PCI-E! Yes, we can now connect high-speed USB drives to the Pi for projects such as media centres and fileservers. We can also boot from USB devices, so adding a cheap SATA SSD via a USB interface will massively speed up your Pi and provide very cheap and plentiful storage for servers.
To power the Raspberry Pi 4 there is a USB-C connector in place of the old micro-USB port. TheUSB-C port provides 5V at 3A (15W), which at idle is approximately 4W and 8W when under load. Since launch a minor flaw has been discovered with the Pi’s USB-C implementation, so it can’t be powered by e-marked USB-C cables–such as those supplied with Apple laptops–this will require a board revision to fix.
While 15W may seem like overkill, it provides plenty of power for the Pi 4 and plenty of spare power for use by USB 3.0 hard drives. The current draw at idle for a Pi 4 is much greater than a Pi 3B+ – 600mA versus 400mA – and so that means a bigger battery is required. In fact, from cold the Pi 4 consumes around 960mA during the boot process.
If you plan to reuse an older official Raspberry Pi power supply (5V at 2.5A, 12.5W), you can purchase an adapter to change microUSB to USB-C. Power can also be provided directly to the Pi via the GPIO, but this will bypass any regulators, so check your voltages before connecting. If you need Power over Ethernet (PoE), you’ll be happy to know that the PoE HAT is compatible.
With all this new power there has to be heat, and this is where the Pi 4 differs to previous boards. To be clear, the Raspberry Pi 4 runs really warm at idle: around 52 degrees C two minutes after booting up. The temp increased to 66 degrees when under load during a Sysbench CPU stress-test. The board can reach temps of up to 80C and so this means that active cooling is a must. We ran the same idle and stress-test sequence on the Pi with a Pimoroni Fan Shim, and this dropped the
idle temp to 36 degrees with the CPU stress-test temp at 46 degrees. We have been advised of an imminent firmware fix that will address these thermals.
Another new feature on the Pi 4 are the dual micro-HDMI ports offering dual screens at 4Kp30, or a single screen at up to 4Kp60. Video is also decoded by a dedicated chip, so there’s no hit on CPU performance. But why is this necessary? Well, to be honest it isn’t something that most users will take advantage of. But 4GB users who may be using their Pi 4 as a desktop replacement can enjoy an extra screen. Typically coders and writers employ two screens for reference and work.
To use the Raspberry Pi 4 we need to be running the very latest version of Raspbian; older versions will not work with the Pi 4 but the latest Raspbian will work on every model of Raspberry Pi. Based upon Debian Buster (unreleased at the time of writing), the latest Raspbian is impressive and nimble. It booted on our Pi 4 in just under 18 seconds and, after a few hiccups, detected our dual-screen setup, giving us 3840x1080 of screen for projects – lovely stuff!
The Raspbian desktop is very usable with Pi 4 and it feels just like a traditional desktop computer. We ran our usual Sysbench singleand quad-core CPU stresstest, and the Pi 4 shaved almost 30 seconds from the Pi 3B+ single-core test: 119.3 seconds for Pi 3B+, 92.7 seconds for Pi 4. In the quad-core tests the Pi 4 scored 23.3 seconds versus the Pi 3B+ time of 31.8 seconds. The Pi 4 also blazed through our Octane benchmarks with a score of 7274, 2.6 times quicker than Pi 3B+.
But where the 1GB version will struggle is with resource-heavy apps – Chromium is the main culprit. Watching a video at 720P in a window is bearable; make it fullscreen and 1080P and it becomes a slideshow. There is a future update planned to address these launch issues, so we shouldn’t have to wait long for a fix.
The questions that the Raspberry Pi 4 raises are “Who is this board for?” and “Why do we need this much power?” To be blunt, the Pi 4 does offer a lot of power, but most makers will not take full advantage of it. The Pi 4 offers entry-level desktop performance and for $60 - $95 that should be applauded. But for most hobbyists who make GPIO-based projects, robots, or who are learning to code, then sticking to a Pi 3B+ and using the latest Raspbian release will offer all the latest Debian Buster features at no extra cost. Anyone looking to upgrade their Raspberry Pi would be wise to wait for a while until Debian Buster and the Pi 4 software gains a little maturity. Don’t get us wrong – the team have done marvellous work with the Pi 4, but the software hiccups need to be ironed out before consumers get their hands on one.
If you have been waiting to run your own low-power Linux home server, then the Pi 4 is the board of your dreams! There’s lots of power, gigabit Ethernet, USB 3.0 and Debian stability. The other bonus for all users, no matter what version is purchased, is the immense library of support and documentation provided by the Raspberry Pi Foundation.