Original: https://www.tomshardware.com/reviews/raspberry-pi-4-b,6193.html
This article is translated by Google, it is recommended to read the original article in English.
The Raspberry Pi has long been the gold standard for low-cost single-board computing, providing a variety of services for robotics, smart home devices, and digital kiosks. The highly anticipated Raspberry Pi 4 takes the Pi to another level, with performance sufficient to serve as a desktop PC, capable of outputting 60 Hz 4K video or powering dual displays.
RASPBERRY PI 4
Pros-
Much faster than previous Raspberry Pis
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USB 3 ports
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Capable of outputting 4K video at 60 Hz
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Dual display support
Cons
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Key software does not work at launch
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Poor performance in high-resolution video playback
Verdict
The best Raspberry Pi is faster and more powerful than any predecessor without increasing the price.
Rating: 4.5 / 5
For the same starting price of $35 as previous models, you can get two to four times the speed, support for USB 3, and true gigabit Ethernet. Perhaps more importantly, there will be a $45 Raspberry Pi 4 with 2GB of memory and a $55 version with 4GB, which is four times that of the previous Pi. Manufacturers and hobbyists alike are eager to add the Raspberry Pi 4 to their arsenal, and now tech enthusiasts who have never used a Pi have even more reason to buy it.
Raspberry Pi 4 Model B. (Credit: Tom’s Hardware)
We had the opportunity to get an early look at the Raspberry Pi 4 B, the full name of the first Pi 4 model, and were able to test the board with a full 4GB of RAM. What we saw was a fully functional mini computer. We were particularly excited about the possibilities for inference, particularly object and sound detection.
Backward Compatibility
It is worth noting that at launch, some important Raspberry Pi software was not yet running on the Pi 4. To run the Pi 4, you will need to download a brand new version of the Raspbian OS called Raspbian Buster. Not everything is compatible with Buster. During testing, we found several
Python libraries or other essential packages that were not compatible with the new operating system.
As of the time of writing, you also cannot install Retropie (a very popular game emulator software) on Buster (trust us, we spent hours trying), nor can you use existing Retropie images. There is no doubt that developers will make adjustments in the coming days and weeks, but if you are reading this at launch and need to build an arcade in the near future, you may want to get an older model. Third-party Raspberry Pi operating systems also need some adjustments to work with the new hardware. For example, we could not boot Windows 10 on Arm like we could with the Pi 3B +.
Key Differences
The table below shows a key specifications comparison between Raspberry Pi 4 B (the first and only Pi 4 model) and Raspberry Pi 3B + (the fastest version of Pi 3).
| Specifications | Raspberry Pi 4 B. | Raspberry Pi 3 B + |
| CPU | 1.5 GHz, Quad-core Broadcom BCM2711B0 (Cortex A-72) | 1.4 GHz, Quad-core Broadcom BCM2837B0 (Cortex A-53) |
| Memory | 1 – 4GB DDR4 | 1GB DDR2 |
| GPU | 500 MHz VideoCore VI | 400 MHz VideoCore IV |
| Video Output | Dual micro HDMI ports | Single HDMI port |
| Max Resolution | 4K 60 Hz + 1080p or 2x 4K 30 Hz | 2560 x 1600 |
| USB Ports | 2x USB 3.0 / 2x USB 2.0 | 4x USB 2.0 |
| Wired Network | Gigabit Ethernet | 330 Mbps Ethernet |
| Wireless | 802.11ac (2.4 / 5 GHz), Bluetooth 5.0 | 802.11ac (2.4 / 5 GHz), Bluetooth 4.1 |
| Power Port | USB Type-C | Micro USB |
| Power Requirements | 3A, 5V | 2.5A, 5V |
| Size | 3.5 x 2.3 x 0.76 inches (88 x 58 x 19.5 mm) | 3.2 x 2.2 x 0.76 inches (82 x 56 x 19.5 mm) |
| Weight | 0.1 lbs (46g) | 0.11 lbs (50g) |
The most important new features are the faster CPU and GPU, more and faster RAM, the addition of USB 3 ports, dual micro HDMI ports instead of a single HDMI connection, and support for 4K output. The higher bus speeds with USB 3 also allow the onboard Ethernet port to support true gigabit connections (125 MBps), where the theoretical maximum for the last generation models was only 41 MBps. The speed of the microSD card slot is also doubled from the original, with a theoretical maximum of 50 MBps, compared to 25 MBps on the 3B +.
Since the new SoC requires more power, the Raspberry Pi 4 B is powered via USB Type-C instead of micro USB. It also requires a power adapter capable of providing at least 3 amps and 5 volts, but if you are not connecting many peripherals to the USB ports, you can use 2.5 amps. Aside from the power requirements, the USB Type-C connector is reversible, making it easier for kids (and adults) to plug in.
Design
The Pi 4 measures 3.5 x 2.3 x 0.76 inches (88 x 58 x 19.5 mm) and weighs 0.1 lbs (46g), making it thin enough to fit in a pocket and light enough to carry around. The board is durable enough to roll around in your bag, but we recommend sticking it in something protective primarily to protect the pins. However, during testing, I always left it bare on my desk and moved it back and forth between work and home multiple times, just putting it in a cardboard box without padding or an anti-static bag.
Unfortunately, if you want a case, you cannot use any cases designed for previous Raspberry Pis. The Raspberry Pi 3 B / 3 B + have nearly the same dimensions, but the port layout has changed enough to make the Pi 4 B incompatible. While previous Pis had a single full-sized HDMI port, the dual micro HDMI connectors on the Pi 4 protrude more, so they won’t align with the holes on anything designed for the Pi 3 B.
The Raspberry Pi 4 covers more than just the basics in terms of ports. On the right side, there are four USB Type-A connections, two of which are USB 3.0. There’s also a full-sized gigabit Ethernet port for wired connections. The bottom edge has a 3.5mm audio jack, two micro HDMI ports, and a USB Type-C power port. On the left side, you will find a microSD card reader. On the top surface of the board, you will see ribbon connectors for the camera serial interface (CSI) and display serial interface (DSI), which provide dedicated connections for Raspberry Pi’s own cameras and screens (or compatible accessories). Of course, you can also connect a camera via USB, along with several common methods, including the micro HDMI port, which can output to a display.
New CPU, RAM
The Raspberry Pi 4 has a similar design and dimensions to its predecessors, but it is a whole new platform powered by the new Broadcom BCM2711B0 processor. Since the first Pi was released in 2012, all Pis used a 40nm SoC, but this new chip is based on a 28nm process and uses the Cortex-A72 instead of the old Cortex-A53 microarchitecture. The BCM2711B0 in the Raspberry Pi 4 has four cores, clocking at 1.5 GHz, and at first glance, it doesn’t seem much faster than the 1.4 GHz quad-core BCM2837B0 in the Raspberry Pi 3B +.
However, the Cortex A72 has a 15 instruction pipeline depth, while the old model had only 8, and it also provides out-of-order execution, so it won’t wait for an output from one process to start another. Therefore, even at the same clock speed (and with the BCM2711B0 based on a smaller process node), the Cortex-A72 processor will be much faster than its A53-powered ancestors and use more power.
For example, in measuring overall computing power with the Linpack benchmark, the Pi 4 absolutely crushed the Pi 3 B + in all three tests. In the most important single-precision (SP) test, the Pi 4 scored 925, compared to 224 for the 3 B +, an increase of 413%.
In the Sysbench CPU test, the Pi 4 B was able to execute 394 events per second, compared to 263 for the Pi 3 B +. This is a 50% difference.
RAM is also significantly faster, moving from 1GB DDR2 RAM on the Pi 3B + to a maximum of 4GB DDR4 RAM. In addition to the increased bandwidth, having more memory is a huge deal, especially for web surfing.
The RAM on the Pi 4 returns read and write speeds of 4,130 and 4,427 Mbps respectively. This is 51% and 54% better than the 3 B +.
When compressing files, both the CPU and RAM are affected. In multi-threaded mode, the Pi 4 B is 37% faster than its predecessor when compressing files, but it is more powerful in single-threaded mode, outperforming the 3 B + by over 60%.
New GPU, Faster Graphics Performance
The GPU has also seen a significant upgrade. It has transitioned from the Broadcom VideoCore IV running at a core clock speed of 400 MHz to the VideoCore VI set at 500 MHz. The new architecture allows it to output to displays at rates of up to 4K fps at 60 fps, or support dual displays at up to 4K 30 Hz.
While we hoped we could try some resource-intensive emulators in Retropie for this review, there was no compatible version with the Pi 4 at launch. However, the OpenArena Benchmark, testing frame rates in a Quake III Arena clone game, did indeed run.
At 720p resolution, the Pi 4 is the only Raspberry Pi that can deliver smooth frame rates. Yes, you can play games on the Pi 3, 3 A +, or 3 B +, but all three of those games have transfer rates between 27 and 28 fps, compared to 41.4 fps on the Pi 4.
Storage Performance
No matter how fast your CPU, RAM, and GPU are, if your storage speed is slow, everyday tasks like opening applications and files will be very laggy. Like all Raspberry Pis, the 4 B’s main storage device is the microSD card reader, which is convenient but a bit limited. According to the Pi Foundation, the 4 B has a maximum transfer speed of 50 MBps, which is double that of the 3 B + reader speed. There are no known capacity limitations.
Our benchmarks were conducted using a Samsung EVO Plus microSD XC Class 10 card, showing speeds that are less impressive than the theoretical maximum. The sequential read/write speeds of the Pi 4 B were 45.7 and 27.7 MBps, while the 3 B + marked 22.8 and 17.5 MBps. Keep in mind that the card is rated for a read speed of 100 MBps and a write speed of 60 MBps. If you have a fast USB flash drive or external SSD, you can achieve better storage performance from the Pi 4 B. The Pi 4 B is the first to have USB 3 ports with a maximum theoretical bandwidth of 625 MBps.
By connecting a 120GB external SSD from Mushkin to one of the USB 3 ports, the Pi 4 B achieved impressive read and write transfer rates of 363 and 323 MBps respectively. This is nearly ten times faster than the 3 B +’s 33 B and 34 MBps marks.
The fast USB 3 ports are not just for storage. You can use other high-bandwidth peripherals, such as Google’s Coral USB Accelerator, which can help complete AI tasks.
Network Performance
The Raspberry Pi 4 has the same 802.11ac Wi-Fi as its predecessors, but it supports Bluetooth 5.0, an improvement over the previous model’s Bluetooth 4. More importantly, the Ethernet port now has more bandwidth, allowing it to deliver full gigabit throughput, while previous models could only reach about 330 megabits.
In testing, the Ethernet port of the Pi 4 B reached 943 Mbps, blowing away the other Raspberry Pis. In fact, in throughput tests, the Pi 4 B’s rate was 943 Mbps (close to the maximum of 1,000 Mbps). This is nearly five times that of the Pi 3B +, which only managed 237 Mbps.
Both old and new Raspberry Pis have 802.11ac Wi-Fi, which can operate on either the 2.4 GHz or 5 GHz band. So we didn’t expect to see a huge performance difference here. But the Pi 4’s 5 GHz throughput is noticeably higher, returning a rate of 114 Mbps compared to 97 Mbps for the Pi 3 B +, which is an 18% improvement.
Power and Heat
Due to the more power-hungry processor and the need for a power adapter that provides at least 5 volts and 3 amps, the Pi 4 is expected to consume more power than its predecessors.
At idle, the Pi 4 B consumes 3.4 watts, which is 17% higher than the 3 B +. Under load, that number jumps to 7.6 watts, but that’s still 19% more than its predecessor. If you want the lowest power Pi, you can choose the Pi Zero W, which consumes only 0.8 watts at idle and 1.6 watts under load.
Yes, this board is warmer than its predecessor. Thermal images reflect what we experienced; the area of the board near the CPU is quite warm, not just the top of the processor itself. The Pi 4 board reached 74.5 degrees Celsius (166 degrees Fahrenheit). This is not hot enough for serious burns, but children should especially be careful to only pick up the Pi by its sides. The top surface of the Pi 3 B + was cooler, with a maximum temperature of 62.5 degrees Celsius (144.6 degrees Fahrenheit).
Thermal image of the Raspberry Pi 3 B +. (Image credit: Gareth Halfacree)
Thermal image of the Raspberry Pi 4 B. (Image credit: Gareth Halfacree)
As with any modern computer, if you push the system too hard and the CPU or GPU overheats, the computer will slow down to avoid damage.
When running CPU-intensive workloads for 10 minutes, the processor reached 81 degrees and began throttling down from 1.5 GHz to 1 GHz after 3 minutes. However, when the system cooled down to around 80 degrees, it still managed to recover to the full 1.5 GHz, but then it would warm up again and drop to 1 GHz. If you want better sustained performance under load, consider installing an active cooler for the Raspberry Pi 4, or at least a passive heatsink.
GPIO Pins
The real star of any Raspberry Pi is its 40 GPIO (General Purpose Input/Output) pins. The number and layout of the pins remain unchanged from previous models, returning to the Raspberry Pi 2, so any “hats,” sensors, or LED screens connected to the Pi 2 or 3 are compatible.
Image credit: Gareth Halfacree)
However, the Raspberry Pi 4 adds some new features to some of the pins. For hardcore makers connecting various peripherals, the GPIO pins now support four additional I2C, SPI, and UART connections. So if your sensors or peripherals require any of these interfaces, you now have more of those interfaces.
On the Raspberry Pi 4, GPIO pin speeds and responsiveness are also much faster, potentially due to its faster processor. Our tests using the gpiozero Python library continuously turned pins on and off and measured the rate at which they switched. The Pi 4 had a speed of 50.8 KHz, while the Pi 3 B + had a speed of only 16.1. This is a 215% improvement.
Using the Raspberry Pi 4 as a PC
One of the goals of the Raspberry Pi 4 is to serve as a powerful PC that anyone can use for internet browsing, light productivity work, and even playing very basic games. To test this use case, I spent several hours getting my work done on the device, and I even used it to write part of this review.
I really appreciated the ability to output to dual displays, which is something I do every day at work and home. And since most of my daily work is done in a web browser, it was no problem using Chromium to write, edit, and research articles. Even with 15 tabs open, switching between them was smooth, and I never exceeded the 4GB of onboard RAM.
While I wouldn’t want to use it every day, GIMP provides a decent way to edit static images. If I wanted to tinker with spreadsheets or write documents outside of Google Docs, Libre Office would suffice.
My biggest issue revolved around video playback. If I wanted to watch YouTube videos, I had to keep it in a window because even at 480p resolution, it was choppy in fullscreen. Another task I wanted to perform was playing retro games, but at the time of writing, the Retropie emulator package was not compatible with the Pi 4. However, I was able to install and play Quake Arena.Keep in mind that the Raspberry Pi 4 can work with several different operating systems, but the most supported is Raspbian, which is a Linux that has a small learning curve for newcomers. Users looking for a low-cost web-surfing computer without any modifications can buy a Chromebook or low-end Windows laptop for $150 to $200.
4K Output, Video Playback, and Transcoding
One of the drawbacks of previous Raspberry Pi computers was that they could only natively output to one display at a time, but if you like multitasking and want to use the Pi to boost productivity, you really need a second screen. The Raspberry Pi 4 has dual micro HDMI ports, each capable of connecting to a separate display or TV and can run at resolutions of up to 4K (3840 x 2160). If you have multiple 4K displays, you have a choice: you can run each screen at 30 Hz, or you can enable 4K mode in the settings menu, which slightly increases the voltage so that you can run one display at 4K 60 Hz and another at up to 1080p.
In extensive hands-on testing, I found that while 30 Hz 4K is tolerable, small things like moving the mouse pointer are a little sluggish. If you have a 4K screen, you’d better choose the 60 Hz mode, but be aware that the increased voltage may also cause the CPU to get hotter and throttle more easily.
Web surfing, enjoying 4K’s extra screen real estate is great, but video playback is the Achilles’ heel of the Raspberry Pi 4, at least at the time of writing. Whether we were trying to stream 4K video or using downloaded files, we could not get a smooth, workable 4K experience on Raspbian Buster or on an operating system running the Kodi media player, LibreElec. Several H.264 encoded videos, includingTears of Steel, simply wouldn’t play or displayed as garbled colors. Even Kodi recommended for the people I tested would show the jellyfish video sample as a still image with no movement. Clearly, there is still a lot of optimization needed in the operating system and software to get the Raspberry Pi 4 to play 4K video.
Unfortunately, even playing 1080p YouTube videos is a challenge. Running at 1080p resolution, the full-screen video trailer forStranger Things showed significant stuttering. However, when I watched the same clip in a smaller window, it played smoothly. Even when I lowered the stream’s resolution to 480p, I encountered the same issues.
If your screen resolution is 1920 x 1080 or lower, offline 1080p video playback is excellent. When I watched the downloaded trailer for Avenger’s Endgame using VLC player, it was very smooth.
The Raspberry Pi 4 will not replace anyone’s MacBook Pro or Dell XPS 13 creative workstation, but if you are patient, it can transcode video for you. Using FFmpeg, the Raspberry Pi 4 transcoded a very short H.264 encoded clip to NTSC DV format in 48 seconds. This is much less time than the Pi 3 B +, which completed it in 108 seconds, but if you want to transcode a full movie, you may need to leave your Pi for a while and come back.
Web Surfing
The web surfing experience on the Raspberry Pi 4 is noticeably smoother than any of its predecessors. The faster processor helps, but having more than 1GB of RAM does too. I noticed in the Gnome system monitor that even with one or two tabs open, I was using over 1GB of RAM. However, with the 4GB Pi 4, I had no problem running more than 15 tabs at once and switching back and forth between them.
While web page rendering is not as fast as a modern Core i7 laptop with Windows 10, the Pi 4 provides a very reliable web browsing experience. I encountered no issues when using Google Suite applications, including Gmail, Google Sheets, and Google Docs.
In Jetstream 1.1, a comprehensive browsing benchmark that measures Javascript processing and page rendering, the Pi 4 outperformed the Pi 3B +, scoring 42.5 to 17.1, which is a 148% improvement, but the Pi is still not as powerful as low-end Intel-supported Chromebooks, such as the Samsung Chromebook 3, which scored 49.7. However, PC laptops performed worse, including the Dell Inspiron 14 3000, which scored only 35.9.
The Speedometer 2.0 benchmark measures overall responsiveness by loading a virtual web application and then simulating user interactions with it. The higher the score for this test, the less latency you should experience when actually using web tools like Google Docs or Gmail. As with Jetstream and real-world scenarios, the Pi 4 leads its predecessors. In this case, it was 98% faster.
Forget about using websites with webGL animations, as they are slideshows, at least with the current software. When I launched the webGL aquarium demo showing 50 fish swimming, the speed on the Raspberry Pi 4 was only 2 fps, while on the Pi 3 B + it was only 1 fps. I thought this would double the speed of the Pi 4, but 2 fps is still useless.
Virtual Hosting
Web services are one of the most common use cases for the Raspberry Pi. In fact, at Tom’s Hardware, we use the Raspberry Pi 3 B as our server on our local network for hosting our notebook battery tests. The Raspberry Pi 4 promises to provide more powerful web surfing with its faster processor, larger RAM, and better network connectivity.
Using Phoronix Apache tests, the Raspberry Pi 4 processes 3,983 requests per second, while the Pi 3 B + processes 2,850 requests per second. This is a 40% improvement, meaning you can serve heavier web pages or more visitors simultaneously without lag.
Many web applications use the PHP server-side scripting language, so processing PHP faster can be a huge help. On the PHPBench measuring PHP performance, the Raspberry Pi 4 B scored 101,540, more than double the 41,351 of the Pi 3 B +.
AI, Inference, and Machine Learning
Perhaps the most exciting new use case for the Raspberry Pi 4 is for inference and machine learning. With earlier Pis, you could do simple object detection with a camera at low frame rates, but the increased performance and I/O of this new model should open up a whole new world of use cases.
To see how the Pi 4 handles object detection, we followed the steps in this tutorial that used a combination of Google’s TensorFlow machine learning platform and OpenCV, a programming library that facilitates computer vision. After spending three hours compiling and installing all the software, I let the application run and watched as the webcam identified a few – very few – objects, including identifying me as a “person” and my chair as a confident “chair.” It ran at a low speed of 1.7 fps, but that was 70% better than when it was running on the Pi 3 B + at 1 fps.
However, with more optimized frameworks, the Pi 4 should be able to perform real-time face and object recognition. And because it has USB 3, accelerators like the Google Coral TPU USB dongle should have more bandwidth to send data back to the SoC. Imagine building a home companion robot that recognizes each member of the household by face, or helping farmers classify cucumbers by type. Some of these workloads could be accomplished on earlier Raspberry Pi computers, but the Pi 4 B should make them fast and accurate enough for regular use. We can’t wait to see what developers and manufacturers do with the Pi 4 and AI.
Scikit-learn is a popular Python module for implementing machine learning. Performing Scikit-learn tasks on the Pi 4 B is more than twice as fast as on the Pi 4 B.
Compiling Code
With Linux, sometimes you have to compile programs to install. During our testing process, we had to compile software packages multiple times, including when we wanted to get the object recognition demo.
The faster processor and better RAM help the Raspberry Pi 4 B compile code faster than its predecessor. When we ran tests compiling the Linux kernel, the 4 B was 33% faster. So whether you are a developer writing your own software or just a user wanting programs to download directly, the Pi 4 can save you time.
Overclocking the Pi 4
We have explained how to overclock the Raspberry Pi 4 and what kind of results you get in a separate article. However, the most important thing is that you can easily boost the 1.5 GHz CPU to 1.75 GHz and increase the GPU frequency from 500 to 600 MHz without missing a beat. Just make sure you have cooling.
How Much Raspberry Pi 4 RAM Do You Need?
The Raspberry Pi 4 B comes in three configurations, the same but with different RAM amounts. The entry-level model at $35 has 1GB of memory, the $45 unit has 2GB, and the $55 SKU goes up to 4GB. One of the big advantages of all Raspberry Pis is that they are affordable for anything, so you need to choose wisely. If you are building a robot or other IoT device that only handles motors and sensors, 1GB is sufficient because you are not running many applications and don’t even need a GUI.
If you are doing very light web surfing, setting up a self-service terminal, or deploying a limited-use web server, we recommend using 2GB. The 4GB model is ideal for using the Pi as a PC or for more complex tasks (like AI).
Conclusion
The Raspberry Pi 4 represents a massive leap, not just for the Raspberry Pi but for single-board computing as a whole. This is the first time it’s realistic to use the Pi as a secondary PC or backup PC (or perhaps the first PC for kids). However, the real benefit comes not from people using Raspberry Pi 4s instead of x86 PCs, but from all the innovators who will leverage the enhanced performance, I/O, and graphics of the system to create new IoT devices, media servers, and robots. The kids building Pi projects in schools will also have a whole new learning opportunity.
However, if you need a Raspberry Pi computer today, you will have to endure some issues that may be resolved through software updates in the near future. Key applications like Retropie do not run on the Raspberry Pi 4, and video playback performance is disappointing. While it’s certain that major applications will be ported to the new computer, we still don’t know how good video playback will be once the operating system improves over time.
Despite these minor issues, the Pi 4 still leads its predecessors and all other low-cost single-board computers on the market. The main question is not: What can the Pi 4 do for you, but what can you do with it?
Editor’s Note: Some of the benchmarks in this article were completed by co-author Gareth Halfacree, who published his own detailed analysis of Raspberry Pi 4 performance on Medium (https://medium.com/@ghalfacree/benchmarking-the-raspberry-pi-4-73e5afbcd54b).
Image Credits: Tom’s Hardware, Gareth Halfacree