tech

Largely due to Apple's transition from x86 to Arm and Microsoft's ongoing support for both architectures, there has been a renewed interest in PCs using Arm processors. At the end of last year, MediaTek expressed its intention to enter the Windows market with Microsoft's backing, and there are reports that AMD and Nvidia are considering offering Arm-based solutions for mobile PCs as early as 2025. With the support of Microsoft and Apple, it seems natural for chip and system suppliers to support Arm-based PCs. However, since their introduction, these two Arm-based platforms have yielded mixed results.

Has the tide finally turned for Arm-based PCs? For Apple, there is no turning back: it is committed to replacing x86. For Microsoft, the situation is more complex.

Microsoft's Moves

Microsoft released Windows Runtime (WinRT) in 2015, enabling Windows support on the Arm architecture for the first time. Although it could run on all Arm v7 compatible SoCs, the first two to be launched were Nvidia's Tegra K1 and Qualcomm's Snapdragon S4. After Nvidia abandoned the Tegra K1, Microsoft shifted towards Qualcomm and its Snapdragon SoC from the end of 2016.

Advertisement

In 2020, Apple replaced Intel x86 SoCs in Mac PCs with its own M-series mobile SoCs, which feature custom Arm-compatible CPU cores. Apple's transition was relatively smooth because it exercises full-stack control over everything, from CPU design to the MacOS operating system. As a result, the Apple platform has even quickly surpassed traditional x86 platforms in terms of overall performance and performance efficiency.

Although the initial Qualcomm-based Windows PCs were marketed as Always Connected PCs (ACPCs), offering light, fanless form factors, multi-day battery life, and cellular connectivity, Microsoft faced difficulties in supporting many traditional (x86) Windows and third-party applications. The new architecture led to numerous Windows 10 updates before the issues were resolved. However, Microsoft did successfully leverage Snapdragon's wireless connectivity to seamlessly support cellular and Wi-Fi communication, a feature that greatly changed the mobile PC user experience.

Qualcomm's Support for Windows

Microsoft's ongoing partnership with Qualcomm comes with an exclusivity agreement that will expire in 2025. The initial Snapdragon-based PCs used the standard smartphone SoC Snapdragon 835. Recognizing the need for a performance and power combination different from standard smartphones in SoCs, Qualcomm launched the Snapdragon 8Cx series in 2019, shifting towards a PC-centric design.

By 2024, Qualcomm will follow in Apple's footsteps by introducing a new series of mobile SoCs designed specifically for mobile PCs, featuring high-performance custom Arm-compatible CPU cores and high-performance neural processing units (NPUs) for AI processing.According to Qualcomm, this new Snapdragon X Elite SoC will surpass its x86 competitors and Apple in terms of AI and overall computing performance. (It is difficult to judge these claims, as these competitors will also be launching new products within the same time frame.)

As AMD, Apple, Intel, MediaTek, and Qualcomm all integrate NPU into their PC SoCs, AI performance is becoming a key metric for future PCs, even for applications that leverage on-device AI processing. However, with Microsoft focusing on integrating its Copilot AI companion into all Microsoft applications and incorporating AI capabilities into Microsoft applications, AI processing performance will soon not only be a key metric but also an important competitive advantage.

Lessons Learned

One of the features that quickly became apparent with early Arm-based solutions is the higher energy efficiency compared to contemporary x86 processors. Windows-based platforms can easily achieve battery life of two days or more. Additionally, most Arm-based Windows platforms typically come with cellular connectivity. This is much like having a mouse or touchpad: once you have it, you never want to give it up.

The ability to connect almost anywhere without searching for Wi-Fi networks changes the game. Combining this feature with smartphone-like instant-on capabilities, mobile PCs with full keyboards and larger screens become the preferred platform for many operations typically performed on smartphones—replying to emails, watching YouTube videos, and even video chatting with friends or colleagues.

Arm mobile SoCs also bring smartphone AI inference processing to PCs through dedicated NPUs.

Both Qualcomm and Apple support AI through their first mobile PC SoCs, which is a continuation of smartphone SoCs that have already used AI for battery management, computational photography, and network connectivity, as well as third-party applications like video conferencing and social networking. It was not until the latest generation of mobile x86 processors that AMD and Intel integrated NPUs into their mobile PC SoCs.

Although there are currently few applications that can effectively utilize the Windows PC NPU, the Arm-based SoCs are driving the market and competition to focus on AI processing.

The one thing that all other platforms still lack, aside from the current Qualcomm SoC, is cellular connectivity. The cost of adding this to other platforms can run into the hundreds of dollars, making it cost-prohibitive for all but the highest-end system configurations.Apple has also demonstrated that, with a focus on performance, custom Arm-compatible cores can compete with the performance of traditional x86 PC SoCs. Unfortunately, PCs based on Apple and Windows Arm have faced significant limitations—namely, a lack of support for high-performance discrete GPUs.

Similar to x86 SoCs with integrated graphics, Arm SoCs are suitable for most applications, but there remain some high-performance applications, such as gaming and STEM (Science, Technology, Engineering, and Mathematics), that require the robust user experience provided by AMD, Intel, or Nvidia. In some cases, advanced applications will not run without a discrete GPU. However, Arm PCs can easily overcome this limitation with support for PCIe interconnects and GPU drivers.

Will there be new Arm PC SoCs?

Among the three major chip companies interested in entering the Windows PC space, only MediaTek has publicly stated its intention to enter the mobile PC market with an Arm SoC, but without providing any details. In the smartphone market, MediaTek has only used Arm's standard CPU cores, similar to what Qualcomm did before its upcoming Snapdragon X Elite PC SoC.

This strategy has resulted in a highly efficient platform capable of multi-day battery life, but it lags behind Apple and x86 competitors in overall performance, particularly in CPU performance. It is currently unclear whether MediaTek is willing to embark on the long and costly path of developing its own custom CPU core technology, nor is it clear whether it will release standard Arm cores that can provide competitive PC performance.

While neither AMD nor Nvidia will confirm or deny the development of Arm-compatible solutions, it seems plausible for both companies.

Both AMD and Nvidia hold Arm architecture licenses, and both have developed custom Arm-compatible cores in the past. AMD developed custom Arm cores for its server processors, code-named Seattle, which were never officially released. Nvidia developed custom Arm-compatible cores for its Denver project, which targeted smartphone SoCs. Project Denver never fully reached the market, but Nvidia was one of the first companies to run Windows on an Arm processor with its Tegra K1 SoC. Note that Nvidia's latest Arm server processor project is named Grace and uses standard Arm Neoverse server cores.

The rumors surrounding AMD and Nvidia are also intriguing because these companies are leaders in the PC graphics space, so they could potentially overcome the current graphics limitations of the Arm platform quickly. Additionally, AMD has built custom SoCs for Microsoft's Xbox gaming consoles, so it could contract with Microsoft or PC OEMs to build Arm SoCs for PCs.

Nvidia has also partnered with MediaTek in the automotive cockpit SoC space. This collaboration combines MediaTek's expertise in mobile/smartphone SoCs and wireless connectivity with Nvidia's expertise in graphics and artificial intelligence. The current partnership is focused solely on automotive cockpit SoCs, but similar efforts could apply to PC SoCs. Such a partnership would give MediaTek an advantage in graphics processing over other Arm-compatible PC SoCs.

If these three industry leaders are considering Arm-compatible solutions for PCs, it is likely that other chip suppliers are as well. However, any company interested in entering this market must invest heavily in custom chip design and software development and will require support from Microsoft. Even with support for the instruction set, the operating system must be ported to the platform. Thus, only Microsoft can reveal which Arm-compatible SoCs will come to market. However, Microsoft has stated that it is committed to developing Arm-based PCs as an alternative to x86, which has long been dominated by Intel.Is it worth investing?

Although PCs based on Arm seem to have a strong argument, challenges still exist. On one hand, Apple still faces challenges in graphics, integrated cellular connectivity, and support for traditional Windows PC applications, but it has been able to transition quickly and quite seamlessly. On the other hand, Arm-based Windows PCs have been a market niche between Chromebooks and x86 PCs, and have not shown any momentum in capturing market share.

Despite Microsoft's support, several OEM manufacturers' PCs equipped with the new generation Snapdragon, and the advantages of Arm-based PCs, there are still many factors fundamentally hindering the adoption of the platform to date.

The first is a lack of visibility. These platforms are not yet available through many common retail channels (even Microsoft Stores), nor can they be seen on OEM websites. Simply finding an Arm PC is already a huge challenge.

The second issue is software. There are still some legacy, highly targeted applications that may only run on x86 PCs, or at least run well, without investing a lot of money to port the software to the Arm platform. Emulating applications works for many (but not all) applications, especially compute-intensive design and engineering applications. Apple still faces the challenge of this issue, but it is working to address it.

The third issue is the convenience of connectivity. With cellular connectivity features, wireless carriers seem naturally interested in selling these platforms, but they have not shown any interest. Until recently, wireless carriers have not provided an easy way to initiate connections, nor have they offered cellular PC data plans consistent with other mobile device plans. However, this situation may be changing. T-Mobile has just announced a 90-day free service for the new Microsoft Pro 9 PC that uses Qualcomm Snapdragon SoC onboard eSIM technology.

The fourth issue is also crucial, and that is differentiation. Arm PCs look and behave like traditional x86 PCs. The platform has no differentiation, except for not being prominently highlighted. Some early Arm-based PCs even have the same PC bloatware, causing them to be bogged down and limiting battery life. Apart from integrated cellular connectivity, Arm Windows PCs currently do not offer a unique user experience, and Intel has partnered with MediaTek to add it to x86 PCs. Without a unique experience, consumers and IT managers considering purchasing a PC are more likely to choose the brands and technologies they are familiar with, especially when these are the first items that appear in searches or on web pages.

There is also the question of why AMD and NVIDIA would consider entering the market with Arm-compatible SoCs, or equipping Arm PCs with discrete graphics cards. Both companies' success in the PC sector is closely tied to the x86 tradition, and the PC market is a mature market that is likely to grow slowly in the long term.

Investing in Arm PCs by AMD and NVIDIA may simply mean taking money from one niche market and investing it in another. Especially for AMD, which has achieved great success in the PC sector in recent years, winning market share. Entering the Arm PC sector requires a significant investment in chip design and software development, which may not be the best strategy for a company that may face fiercer competition from Intel in the future.Intel has also developed custom Arm cores in the past. Intel developed the XScale architecture for smartphones, but this achievement was sold to Marvell in 2006. Intel still uses standard Arm cores in various applications, but has not shown interest in supporting Arm PCs. Intel CEO Pat Gelsinger recently responded that this potential threat is "quite trivial."

Are there other options?

Developing a custom CPU architecture is not easy, and developing for a specific instruction set architecture (ISA) can improve efficiency. However, this does not rule out supporting other ISAs.

Companies such as Marvell's Octeon processors and Synopsys' recent Arc processors have proven that they can switch to different ISAs. The Octeon processor migrated from MIPS to Arm, and Synopsys has just released a new Arc product series called Arc-V, which will support the RISC-V instruction set.

Therefore, if a company is investing a lot of money to develop a custom CPU architecture for PCs, considering RISC-V may also be in their best interest. The ecosystem is not mature, but it offers more instruction set flexibility and no royalties or licensing fees. Of course, this still requires support from Microsoft, but this may be another option that Microsoft should consider, especially considering China's strong interest in RISC-V.

What is the future of Arm PCs?

Ultimately, although there seems to be renewed interest in Arm-based PCs, the only one that can guarantee success is Apple, which has made a complete transformation and never looked back.

Despite the efforts of Qualcomm and Microsoft, the Windows ecosystem has not effectively promoted the widespread adoption of Arm PCs.

The Windows ecosystem for Arm PCs needs more support from OEMs, carriers, and even retail channels to affect consumer and enterprise purchasing patterns. Arm-based Windows PCs have become a reality, but they make little difference from x86 PCs and have little impact on the market, but this does not stop Microsoft and Qualcomm from investing in Arm-based Windows PCs.

Similarly, Microsoft continues to invest with other members of the x86 community to develop more competitive solutions.Time will tell whether, in the second wave of Arm-based PCs, the Windows ecosystem will rally around alternatives to x86 PCs.