Microsoft adds x64 emulation to Windows on ARM, but performance is far behind M1 Macs

The performance of both native ARM-based and emulated 64-bit Intel-based software on a Surface Pro X isn’t even close to the new Macs powered by Apple’s M1 laptop chip. “Windows on ARM needs a miracle,” according to one publication which ran various benchmarks to see how Windows on ARM compares to macOS Big Sur running on Apple silicon.

Windows on ARM is a Windows version optimized for processors that are based on CPU blueprints from the fabless semiconductor company ARM Holdings. But it comes with a significant drawback: it does not support 64-bit apps written for the AMD and Intel chips.

The advent of Apple silicon Macs has accelerated Microsoft’s plans for Windows on ARM so much so that the Redmond giant released the first preview of x64 emulation for PCs powered by Windows on ARM. With it, users with an ARM-compatible machine such as the Surface Pro X can now use 64-bit Intel apps that have not yet been optimized for the ARM instructions set.

It works similar to Apple’s Rosetta software in macOS Big Sur which lets you run Intel apps on M1 Macs by emulating the x86 instruction set on the M1 at the expense of performance. As a result, Windows on ARM PCs are now able to run 64-bit Intel apps in Rosetta-like emulation.

But as PCMag reports, performance leaves a lot to be desired.

The site writes:

Now that Microsoft has shipped its own 64-bit emulator, we can more directly compare how well Windows on ARM compares to macOS on ARM. We already had a good idea of how slow Microsoft’s Surface Pro X is—that was evident from our original review. But these benchmarks provide insight into just how slowly the Surface Pro X and its SQ1 chip run with the new 64-bit X86 instruction emulator layered on top.

The Geekbench 5 benchmark revealed that the M1-powered MacBook Air has basically left the Surface Pro X (which uses an ARM-based SQ1 chip co-developed by Microsoft and Qualcomm) in the dust when it comes to synthetic CPU benchmark (we should point out that PCMag’s testing relied on the first-generation SQ1 processor rather than its improved SQ2 variant). Also, Microsoft’s 64-bit x86 emulation is currently in beta while Rosetta 2 is a shipping product.

Up next, Maxon’s Cinebench:

Cinebench paints a rendered two-dimensional image. Macworld jumped to the most recent R23 benchmark, which uses a more complex image than the R15 version PCWorld has used. The new R23 release supports Apple silicon, with no specific optimizations for the SQ1 or Qualcomm’s Snapdragon chips. Nevertheless, Windows on ARM running on the Surface Pro X isn’t even in the same league as the Apple Macbook M1.

And here’s the Cinebench benchmark chart:

The next test used HandBrake, an open-source video-transcoding tool that runs natively on M1 Macs and Intel-based Windows PCs. “The SQ1 chugged along at about a frame per second, taking about two hours to transcode a 12-minute 4K video, Tears of Steel, into a 1080p H.265 format,” the article notes. “Apple’s MacBook M1 simply blows away the Surface Pro X.”

While these benchmarks show just how far behind Windows on ARM is compared to Apple’s new M1 Macs, I’m expecting Microsoft to double-down on this project now that Apple has leapfrogged the rest of the industry.

Inevitably, I think, the rest of the industry will move away from Intel chips and embrace the ARM platform. In other words, give it a year or two (or three) and all notebooks will be as fast and power-efficient as these new M1 Macs. For that to happen, however, Microsoft will need to work very closely with industry partners like Qualcomm to create an ARM-based notebook chip that would be capable of rivaling the M1 chip from Apple.