One of the best-selling computers in all of history is not a conventional computer. It is the Raspberry Pi, a miniPC that in its different versions has managed to sell around 20 million units.

Lovers of this unique device have long been waiting for a unique and less evolutionary jump in their hardware configuration, and although there are hardly any details of what will be the Raspberry Pi 4, it seems clear that it will be a very special model. This is what we know and what we expect from a product that has changed (a little) the world and for which, yes, we might still have to wait.

More than a year waiting (and what we have left)

The own Eben Upton, creator of the Raspberry Pi, confirmed in early 2018 that there was still more than a year for us to see the Raspberry Pi 4, but shortly after, in April 2018, launched the Raspberry Pi 3 Model B +, a slightly improved version of its predecessor.

The improvements to that model were certainly striking both in connectivity (dual band WiFi, PoE support) and in power, with a somewhat forced version of its processor, but except for those changes there were hardly any developments despite the fact that the competition has been on time trying to outdo the RPi where their own users demand more.

The thing did not change when in January 2019 the Raspberry Pi Foundation presented the so-called Raspberry Pi Compute Module 3+ (CM3 +), an additional version of the Raspberry Pi 3 that adopted that “industrial” format.

In the release notes the creators of these devices said that this would be “the last of a family of products based on 40 nm lithography“, which made it clear that the changes that awaited the Raspberry Pi 4 would start with more efficient processors.

What we know about the Raspberry Pi 4

The truth is that the leaders of the Raspberry Pi Foundation have not given too much news in the hardware field since then, and have barely offered details about their upcoming projects.

However, they have confirmed that they are working on the next version of the Raspberry Pi. Eben Upton spoke with Tom’s Hardware and also confirmed that it will be called Raspberry Pi 4. “It would be crazy not to call it that,” he explained.

He also revealed to this publication that we will still have to wait some time for the appearance of this model: ” I have no plans to make any announcements this year, I think we understand more or less what set of characteristics we want and what it would be like to reach that set of characteristics I do not think we have a definite plan yet to turn that into a product for now.” Regarding the confirmed changes, although in many cases without too many details, this is what we know:

• Goodbye at 40 nm: there will be a change of lithography, as indicated in the announcement of the Raspberry Pi Compute Module 3+. In the interview with Tom’s Hardware he explained that “basically we have reached the maximum performance for that process node [lithographic”]. Although they have not decided on the type of processor that will govern it, it seems that the next step is some 28 nm SoC, still far from the 7 nm that are handled in mobile ARM processors. The problem, he says, is that “in smaller process geometries it is more difficult (or at least more expensive) to manufacture inputs that can survive voltages of 3.3 V applied to them, or outputs that can reach 3.3V ” However, the lithographic scale may be somewhat more advanced than 28 nm, but one thing is certain: the improvement in efficiency and power that this will allow will be sensitive. They speak of the Cortex-A55 as clear candidates, something that would allow to improve the performance in a 20% of average with respect to the current RPi. Nothing is known about the potential support of 64-bit instruction sets.
• Price: this is another of the key elements of the Raspberry Pi 4: for years these devices have become famous for that price of $ 35 that starred in stores, although in reality the final price could be slightly higher in different regions. In addition, to put them in operation it is necessary to have some peripherals such as a Micro SD card or the power adapter, for example, and all of them are adding small costs to the final product.
• Physical format: we will probably not see significant changes in the physical design of these miniPCs that are sold as small “raw” plates, which is precisely why they have a special charm. Of course: neither increase nor significantly decrease in size, and for example Upton explained that “I can not imagine going to formats smaller than the Raspberry Pi Zero.”
• USB-C (maybe): the connector used so far to power the Raspberry Pi has been the Micro USB, but it seems that they are seriously considering the USB-C although nothing is certain. With it it is possible to reach the 3 A of power, something important to feed more peripherals although that could generate more heat dissipation. Still Upton is not clear about not being a specially protected connector and also prone to dirt and dust are introduced into it.
• Ports : It seems that Upton was happy with the port selection of RPi 3B / 3B +, so we might not see significant changes to those four USB, HDMI, Ethernet and Micro USB ports for charging.

What we expect from the Raspberry Pi 4

For asking not to be left, right? Well, maybe not so much. Although we would like the future Raspberry Pi 4 to be much more ambitious in all sections, we must be consistent: a $ 35 computer has to make many concessions.

Even so, it is worth bearing in mind that in these years the technology has advanced enormously and it is possible to access much more advanced chips and components than when the first RPi appeared and to do so at reduced costs. That makes us think that our particular “letter to the wise men” is not so difficult to fulfill.

In fact, we are seeing alternatives appear in the market that precisely give an idea of what we could expect in this area. One of them is for example the Rock Pi 4, based on a CPI Rockchip RK3399 hexa-core with two ARM Cortex-A72 cores at 1.8 GHz and four ARM Cortex-A53 cores at 1.4 GHz. There are 1 GB versions ($ 39), 2 GB and 4 GB of LPDDR4 RAM (the latter costs $ 75), and the GPU is an ARM Mali-T860 with support for DX11, Vulkan 1.0, and Open CL 1.2.

We also have four USB 3.0 ports (type A) and even a USB-C port, and although there is no built-in internal storage, there is a microSD slot and, attention, up to an M.2 slot and another eMMC that give a surprising versatility to this product. Of course some of the ideas that we would like to see in a Raspberry Pi 4 are implemented here, but let’s see in summary what we expect from this future model:

• More power: it is something confirmed that the CPU will change, and although here those 28 nm that could be the evolutionary leap could limit things somewhat, it would be interesting to have a CPU that takes full advantage of that lithography. The Cortex-A55 cores we talked about earlier seem like a good choice in terms of performance / efficiency balance. It would also be interesting to have native support for hardware decoding of the HEVC codec, especially considering that many users take advantage of their Raspberry Pi as Media Centers.
• More memory: if we want to work with more room for maneuver, the amount of RAM would be a section to improve, and since the RAM has dropped in price, we may be able to see at least 2 GB LPDDR3 or even LPDDR4, also depending on the processor chosen one.
• Gigabit Ethernet (really): although the last RPi boasts of this connectivity, it is actually limited to about 40 MBps (320 Mbps) of transfer speed through the use of a single USB 2.0 channel shared by this connector and the four ports USB plate.
• Open GPU: A common criticism of the current Raspberry Pi is that the GPU integrated into the SoC (a 400 MHz dual-core VideoCore IV chip) is not “open”, something that limits the CPU and prevents it from going faster by means of a throttling system, as this expert explained.
• USB 3.0: the use of a newer USB standard would allow to advance not only in the transfers of files with external units, but also in the behavior of the network port, which could reach its potential and not be covered by the USB protocol as in the case of the news
• Internal storage: the Micro SD slot is of course an interesting option, but perhaps it would not be a bad idea to integrate a small storage space, perhaps of 8 or 16 GB eMMC, to be able to store in it the operating system without relying on external cards. That would make the price more expensive, so we doubt that the Raspberry Pi 4 will go that way. What can be done is, as in that alternative cited, integrate M.2 slots and eMMC to connect this type of media and use them instead of the slower microSD cards.
• Support Windows 10: in fact there is already partial support for Windows 10 in the Raspberry Pi, but its operation is very limited and makes it clear that nowadays this operating system is not a good option to use with an RPi. Even so, it would be very interesting to be able to take advantage of one of these devices as a conventional desktop PC, something that we can already do with the latest versions thanks to fantastic Linux distributions such as Raspbian.