Raspberry Pi 400 Performance

Is Raspberry Pi 400 performance, heating, ergonomics finally achieved? The Raspberry Pi 400 finally arrived in the lab in its AZERTY version. In addition to its all-in-one aspect, it promises a higher operating frequency with finally controlled heating. But is it necessary for all that to crack? The Raspberry Pi 4 has not been a great success. Of course, its performance is on the rise, as is its connectivity. We finally had a 1 Gb/s network, USB 3.0 and a Type-C power supply. But a lot of things went wrong. Some saw it as a sign of overwork on the foundation side.

Raspberry Pi Foundation and v4 card: it’s hot!

Thus, compatibility with USB Type-C for power required a hardware fix. USB booting only happened recently. We are not even talking about the 64-bit edition of Raspberry Pi OS which is still being tested, pushing many users to turn to Ubuntu (now offered in Desktop version).

But the biggest problem was the design of the card itself and its accessories. The SoC was way too hot not to come with a heatsink or fan. Even without a case, the chip quickly overheats and goes into safety (throttling), drastically reducing frequencies and performance.

The official case was not adapted at all , quickly becoming a furnace and no solution has really been found. For over a year, the subject has most often been avoided, put aside. Except when it was a question of improvements on the firmware reducing the phenomenon without providing a real answer.

What push some users to look elsewhere. We understand all the more that NVIDIA has decided to pass the accelerator on its Jetsons by offering a model with 2 GB of memory at 59 dollars.

In recent months, however, the foundation has continued to act like nothing has happened. She declined her card in models up to 8 GB of memory. Then in the form of a Compute module accompanied by a new welcome card. Then, in early November 2020, it announced its Model 400. First to avoid overheating.

A Raspberry Pi 4 in a keyboard

How? ‘Or’ What? Well simply by adding a large heat sink. A format facilitated by the fact that the box is now a keyboard. An idea that appeals to the nostalgia of those who lived through the Commodore 64 era, born during the era of home peripheral design, but which took time.

The idea was initially to take the plunge with the Raspberry Pi 3, but it was not possible. Meanwhile, amateur hackers have adopted the concept which is now an industrial reality. If the resemblance is striking with some DIY projects, there are still big differences.

First of all the motherboard has been modified. All in length, it uses the main connections of the basic model with a few exceptions. A USB 2.0 port is indeed sacrificed for the internal connection of the keyboard. We must also ignore the CSI / DSI connectors for a camera or a screen. The same goes for PoE.

By analyzing the PCB and reading Canonical’s initial blog post (which mentioned this possibility), we thought it would be well integrated. But no, and we have verified it: it is impossible to feed the card in this way. The GPIO pins are on the other hand well in the game, directly accessible at the back of the keyboard. The foundation nevertheless recommends an extension cable to make it more practical for everyday use.

The main components do not change. We therefore always have Bluetooth 5.0 and Wi-Fi 5 in addition to two micro HDMI 2.0, two USB 3.0, one USB 2.0, a 1 Gb/s network port and Type-C power. Unfortunately, the card is not sold on its own, and therefore cannot be integrated into third-party projects at this time. Also note that you cannot use the Raspberry Pi 400 as a simple keyboard for a third party computer.

A faster SoC, no built-in storage

One would have thought that for such a product, the foundation would choose preinstalled storage, but this was not the case. No doubt to reduce costs. The Raspberry Pi 400 is in fact sold at 74.5 euros on its own, for a little less than 110 euros in a complete kit with mouse, (micro) HDMI cable, power supply and 16 GB microSD card.

Good news, USB booting is natively supported. You don’t have to make any changes or updates. We used a SanDisk Extreme 1TB v2 USB 3.2 external SSD for the tests without any problem.

The SoC is unchanged: a Broadcom BCM2711 (4x Cortex-A72, ARM v8). But its frequency goes from 1.5 to 1.8 GHz, the team specifying that we can even go beyond. She finally seems to have understood the interest of a heat sink and opening allowing the escape of hot air (under the keyboard). And the result is rather there.

We reused the same protocol as in our first tests of the Raspberry Pi 4, with the same Python script for monitoring frequencies and temperatures, as well as OpenSSL running in a loop. And we do not exceed 54° C even after several hours of continuous testing. When cold, the machine displays 24/25° C. Raspberry Pi 400 Stress test. Despite several hours of stress test, the temperature does not exceed 54° C.

Thus, the frequencies do not move. The performances are therefore very good, and stable. Note that we found better results under Raspberry Pi OS than Ubuntu Desktop, hence our choice for this report:

  • Raspberry Pi 4 – OpenSSL RSA 4096 bits:
    1 CPU: 25 signatures/s, 1893 signatures/s
    4 CPU: 99 signatures/s, 7571 signatures/s
  • Raspberry Pi 400 – OpenSSL RSA 4096 bits:
    1 CPU: 30 signatures/s, 2272 signatures/s
    4 CPU: 118 signatures/s, 9085 signatures/s

The operating frequency having increased by 20%, quite logically the performances show a strictly identical ratio. The consumption at the outlet remains contained between 5 and 10 watts.

Ergonomics can do better

The keyboard itself is compact (286 × 122 × 23 mm), lightweight (384 grams), without a physical number pad. It is comfortable to use with its chiclet keys, displays a raspberry in place of the usual Windows logo. At the top right, three clearly visible LED are present to indicate the status of the numeric keypad, the capital letter and the power supply.

However, we have some regrets. First of all, like on a classic Raspberry Pi, there is no physical “Power” button. Still, there was room. You must press F10 to turn on the machine; Fn + F10 to force its extinction (long press). Nothing is planned for a simple restart, you have to unplug then plug in the device.

Many keys also require pressing Fn. Nothing is indicated concerning multimedia functions (volume, tracks and other shortcuts). Pity. We would also have liked more space between the connectors, especially USB. They are on top of each other, causing a problem as soon as the products to be connected are a little wide. Another downside: the power is stuck between the USB and HDMI rather than at one end.

If the “machine in a keyboard” aspect is fun, you will need to allow enough slack in the cables so that this does not pose a problem on a daily basis, the machine being at the level of your hands. If you’re a little rigid about cable management, this product is clearly not the computer for you.

It should also not be forgotten that, although the Raspberry Pi foundation presents its v4 as capable of being used as a desktop computer, it is still quite slow for many tasks. The interface is not always smooth, under Raspberry Pi OS, Manjaro or Ubuntu. Work is still needed on this point.

The Raspberry Pi 400 can therefore be seen as a first PC for your child, an educational or auxiliary machine if you really don’t have big needs. But don’t expect more. But all this, a classic Raspberry Pi 4 can already do it, with the keyboard of your choice (except the best native dissipation).

Finally, no dark model is offered. You don’t like white / raspberry? Pity. Do not expect to be entitled to a Bépo or Azerty + version either, only certain languages ​​are available for the moment.

What’s the point?

The other question that arises is that of scalability. What was appreciated until the Raspberry Pi 4 was the possibility of reusing the same box as the cards evolve. Will this be the case here? Impossible to say. We could have imagined a model using the Compute Module for this, but this is not the choice that was made. When a Raspberry Pi 5/500 is offered, will it be reusable? We will see.

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