Why are there no ARM-based routers

ARM: processor architecture for smartphones, tablets & Co.

It is a success story that is reminiscent of Apple or Microsoft, and yet is somehow completely different. With starting capital of just £ 200, two friends founded the Acorn company on December 5, 1978 in a kitchen in Cambridge, England. They named their self-developed processor ARM - Acorn RISC Machine - Acorn, because they wanted to appear in the phone book before Apple. In the early 1990s, however, such rivalries were over when the ARM chips were further developed together with Apple for use in Newton's personal digital assistant.

Both Apple's company shares and the Acorn name disappeared, but the processor design remained - to this day. The abbreviation ARM stands for Advanced RISC Machines and with ARM Limited it also stands for a billion-dollar company that dominates the market for smartphone and tablet processors - it does not manufacture any itself. ARM only creates designs for processors and then issues licenses to other manufacturers. They manufacture the chips themselves or have them manufactured by specialized companies from the semiconductor industry (foundries). The licensee pays a fee to ARM for each chip produced. Many manufacturers also use ARM designs as building blocks for developing their own more complex systems. The British customers include Apple, Samsung and HTC, but also the CPU manufacturer heavyweights Intel and AMD.

RISC vs CISC: ARM and Intel in comparison

The processor is, so to speak, the "brain of the device". It controls all the important functions of a smartphone or laptop and ensures that the hardware does what it should. The choice of the CPU, the main processor, is accordingly important. In order for everything to work smoothly, it has to execute millions of commands in a very short time. However, the faster the processor, the higher the energy consumption and the shorter the battery life.

To put it simply, the main difference between Intel and ARM is the instruction sets used, i.e. the number of instructions that the processor can execute. ARM processors use a so-called RISC architecture (Reduced Instruction Set Computing), while Intel uses a CISC architecture (Complex Instruction Set Computing). RISC instruction sets are smaller and less complex than CISC instruction sets. Their computing power is correspondingly lower, but they are more energy-efficient than their Intel counterparts. Intel processors are therefore mainly used in desktop PCs and laptops. ARM processors are ideal for smartphones and tablets.

Overview: ARM models from 1985 to today

Of course, there is also a broad spectrum between the various ARM device categories in terms of computing power and energy requirements. While the systems used in high-end smartphones often have clock rates of well over 1 GHz and several processor cores, the ARM range also includes numerous processors and microcontrollers with significantly slimmed-down performance data. Our table shows how the ARM models have developed over the years:

TactDMIPS / MHzcommitment
1985ARM14 MHz-BBC Master (PC)
1986ARM28-12 MHz0,5Acorn Archimedes (PC)
1989ARM325 MHz0,5
1991ARM612-20 MHz
203-206 MHz
0,889Apple Newton (PDA), Acorn Risc PC
1994ARM740-59 MHz0,889-0,9Cell phones and game consoles (including Game Boy Advance, Nintendo DS)
1998ARM9180-200 MHz0,9-1,25
2002ARM11412-1,000+ MHz0,6-1,54Automotive technology, smartphones, routers
2004Cortex-Mup to 400 MHz1,25-2,14 
Smartphones, tablets, laptops, digital televisions, set-top boxes
2011Cortex-Rn / An / A
(64 bit)
1.2-3.0 GHz2,3-4,9
Status: December 2020

Inexpensive and durable: This is where ARM processors score

The energy-saving ARM processors make sense not only in cell phones and smartphones. ARM-based processors are also used in many other devices such as printers, routers, televisions, hard drives, TV set-top boxes or game consoles as well as other portable devices such as digital cameras, audio / video players, handheld games or navigation devices installed. Overall, devices based on ARM are significantly cheaper than those with complex Intel processors. In the tablet area in particular, where both ARM and Intel are installed, there can therefore be noticeable differences in price and performance.

More performance: the Big.LITTLE concept

The Big.LITTLE concept was introduced by ARM in 2011 with the Cortex-A7. In order to achieve the highest possible computing power with low energy consumption at the same time, a comparatively weak but energy-saving processor like the A7 is used in combination with a powerful but energy-hungry processor like the Cortex-A15. The A7 takes on classic, undemanding functions such as the simple operation of the smartphone. The more powerful A15 switches on as soon as more power is required.

So when the user checks their e-mails or surfs the Internet, the weak processor runs and the battery is less stressed. If more demanding applications such as games or videos are started, the powerful processor steps in and improves the performance of the device. In this way, cheap smartphones can provide more power and expensive high-end devices can achieve longer battery life. One of the first devices with Big.LITTLE architecture was the Samsung Galaxy S4.

Systems on a Chip: Tegra, Snapdragon and OMAP use ARM CPUs

Nvidia Tegra 4: The System on a Chip is based on the ARM Cortex A15 architecture
Image: Nvidia If you use a tablet or smartphone, it is very likely that you are using a processor with ARM architecture: More than 90 percent of all cell phones manufactured have an ARM-based processor. As a rule, so-called one-chip systems (System on a Chip: SoC) are used, for example the platforms Nvidia Tegra, Qualcomm Snapdragon and Texas Instruments OMAP. In addition to the processor core, these also contain other elements such as a graphics processor. Snapdragon is particularly popular in the smartphone sector, while Tegra chipsets are often found in tablets. Texas Instruments, however, has now largely withdrawn from the market for smartphone and tablet chips. The pressure on the part of the manufacturers was too great, who were increasingly relying on developing their own chips instead of buying from Texas Instruments. OMAP processors are therefore mainly found in cars and household appliances.

One-chip systems
with ARM architecture
It does happen that a cell phone manufacturer relies on several SoC platforms: Depending on the model, Samsung installs either Snapdragon, Tegra or in-house developments. The ARM-based SoC platform developed in-house by the Korean company is called Exynos and is installed in the Samsung Galaxy S7, among other things. Samsung also produces SoCs for other companies, such as the A7 for Apple. The SoC for use in the iPhone and iPad was developed by Apple itself, manufactured by Samsung and is based on the ARM processor design - a real joint effort.

Windows RT: Microsoft also relied on ARM tablets - and failed

ARM-based tablet from Microsoft:
The Surface with Windows RT
Photo: Microsoft Microsoft Windows is also available in an ARM-compatible version: Windows RT. The operating system variant for ARM-based devices should help Microsoft to catch up on the tablet market. In parallel to the RT tablets, tablets with Windows 8 came onto the market almost simultaneously. The latter run with systems based on Intel's x86 architecture, which has dominated the PC sector for 20 years. Since the introduction of Windows RT, there have temporarily been two types of Windows tablets: ARM-based devices with Windows RT and devices with Intel processors based on x86 with Windows 8 or 10.

But the Windows for the ARM platform was not a lucky star. Not only the in-house ARM tablets Microsoft Surface RT and Microsoft Surface 2 became slackers, Windows RT devices from other manufacturers such as Asus, Samsung and Dell also gathered dust on the shelves. The main reason was the lack of compatible apps. Since ARM CPUs use a different instruction set than Intel processors, only programs from the Windows Store can be installed on the Windows RT tablets, but not from other sources, as is possible under Windows 8 and Windows 10. The ARM-based Windows turned out to be a colossal flop.

Windows 10 for the ARM platform

The Windows RT developed for ARM processors was essentially a stripped-down version of Windows 8. Consequently, many RT users hoped for a corresponding update to the next Windows version for their RT devices as well. A Windows 10 update for the Surface RT then came, but the mini update could not be compared with the PC version.

Meanwhile, with "Windows 10 on ARM", ARM has made a more detailed attempt to gain a foothold, especially in the tablet segment. Since November 2017, the ARM-compatible Windows 10 version has been available in various tablets, such as the Microsoft Surface Pro X. Microsoft uses a Qualcomm SQ1 there. For many users, however, the problem with this choice is that 64-bit * .EXE programs do not run and 32-bit apps only run in a slow emulation. From this point of view, it is questionable how long this type of ARM-based Windows 10 will last. In any case, it has not yet been possible to gain large market shares.

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