Surface Pro: Arm or x86? The answer is not that simple

According to the rumor mill, Microsoft is about to unveil the newest member of the Surface family. If these leaks from Redmond are true, the new Surface Pro 9 offers an unusual configuration option: you can choose between an Arm-based CPU or this year’s latest x86 CPU from Intel.

However, here’s the funny thing. Microsoft has been offering this choice for about a year with the SurfacePro 8 (powered by an 11th Gen Intel Core i7) and the Surface Pro X (with a Qualcomm Arm-based Microsoft SQ1 or SQ2 processor). Having used both devices extensively over the past few months, I still can’t decide which I prefer.

Review: Surface Pro 8 with LTE: Still in love

While the Surface Pro 8 and Surface Pro X are remarkably similar in terms of hardware, there are a number of odd little design differences between them. Each machine has two USB-C ports, but they’re on different sides. The Surface Connector is in a slightly different location on each model. The compartment that allows quick access to the NVMe SSD (and the SIM slot on the Pro X) is on a different side under the kickstand on each model.

The Pro X is slightly thinner than the Pro 8. It’s also lighter, at 275g compared to the Pro 8’s 313g. (That’s the weight without the Type Cover.)

Since both of my devices have a matte black body, it’s really difficult to tell the difference between them without careful inspection.

But in operation there were many differences.

The biggest difference: battery life

You’d expect the arm-powered Surface Pro X to have significantly better battery life than the Pro 8. But my observed battery life on these two devices, as measured using the Windows Powercfg utility, isn’t all that different: if I’m taking the Surface Pro 8 on the go, I can count on a battery life of around 6 hours. If I go for the Surface Pro X, I get just over 7 hours of use.

That doesn’t seem like a big difference, does it? Ah, but those numbers are misleading. You see, the Pro 8 has a fairly beefy 50,230mWh battery, while the battery in the Pro X is significantly smaller at 38,200mWh. (That also explains the weight difference between the two machines.)

If the Surface Pro X had the same battery as the Pro 8, you would expect the battery life to increase by 31.5% (the difference in battery capacity). That would mean nearly 10 hours of actual, real-world battery life compared to 6 hours for the x86 design. When the Arm and Intel versions of the Surface Pro 9 have the same battery size, it’s reasonable to expect similar differences.

Connectivity: A slight advantage for Arm

The Surface Pro X includes a cellular option (with physical SIM and eSIM support) on each model for an additional $150. If you want mobile data on the Surface Pro 8, you need to buy from the Surface for Business storeand you pay an extra $250 for the privilege.

Likewise: eSIM vs SIM: what’s the difference?

I’ve used my Pro X’s cellular modem extensively with a T-Mobile SIM. It works flawlessly and is a great alternative when I’ve been out and about without WiFi.

Cheap and easy memory upgrades

In the past, the Surface Pro was a sealed device, absolutely hostile to any type of repair or upgrade by the user. With the Surface Pro 8 and Pro X, Microsoft not only made memory upgrades possible, they made them easy. I picked one up 1TB SSD (NVMe, in an M.2 2230 package), for a little less than $200. Microsoft charges $600 more for a Surface Pro with a 1TB SSD than the 256GB model. That’s a pretty big savings!

Earlier I mentioned the compartment under the stand. For both models, release the cover the same way you would open a SIM slot on a cell phone, by pushing a SIM eject tool (or a curved paper clip) into the small hole in the cover.

To get that out of the way you need a Torx T3 screwdriver to remove the single screw holding the SSD. Slide out the old drive, insert the new one, pop the cover back on, and use a recovery drive to install a fresh copy of Windows. It was a remarkably easy process on both devices.

Compatibility: Welcome to the gotcha zone

Windows 11 runs exceptionally well on both devices and I had no problem installing the latest version, version 22H2. The x86 compatibility layer on the Surface Pro X is surprisingly good for the most part. It runs all the productivity software I normally use, including Microsoft Office, Adobe Acrobat, and Snagit. It even runs the Windows subsystem for Linux without complaint.

But every once in a while, a compatibility issue pops up to remind that Arm isn’t x86.

For example, when I was in Portugal a few months ago, I had to use a VPN to convince some US-based websites to show me the content I subscribed to. I wanted to use the highly rated ExpressVPN, but as I found out after an hour or two of tinkering and Googling, its network drivers don’t work on Arm-based devices, and there’s no workaround.

In fact, drivers are the Achilles’ heel of Arm-based Windows. Most x86 apps install and run fine, but drivers must be compiled for ARM or they won’t work. This applies to network and file system drivers as well as hardware. For example, I had no connection problems Logitech’s nifty little keyboard/touchpad combo K400+ with the Pro X via Bluetooth, but I couldn’t run the configuration utility to optimize the touchpad’s scrolling direction.

And oddly, I couldn’t boot the Pro X using a recovery drive with a USB Type-A to Type-C adapter. This configuration works on the Surface Pro 8, but for the Pro X it refused to boot. In order to restore the operating system, I had to create a recovery drive on a USB-C flash drive.

These are all pretty minor issues, the kind of hassles you run into every other month. As a basic productivity device, the arm-powered Surface Pro X makes a compelling case. As an all-purpose PC replacement, those pesky compatibility issues can be a deal breaker.

And one last note: the Surface Pro 8 supports Thunderbolt; the Pro X doesn’t. That somewhat limits the docking and expansion options for the Pro X, but that consideration is only relevant if you intend to use it as a desktop replacement. The Surface Pro 9 will probably support Thunderbolt 4 in both configurations.