Many Surface Pro 6 and Surface Book 2 models are suddenly being throttled

Surface Book 2
(Image credit: Future)

Microsoft's Surface Pro 6 and Surface Book 2 are running into some crippling issues, as processor (CPU) clock speeds throttle down incredibly low speeds, TechRepublic reports. The report comes from user complaints that indicate their machines' Intel processors are slowing down to as low as 400MHz.

For reference, the lowest-spec Surface Pro 6 runs an Intel Core i5-8250U processor, which normally clocks at 1.6GHz. That's four times faster than the throttled speed users have experienced. And, that CPU can boost up to 3.4Ghz, more than eight times faster than the reduced clock speed.

The culprit for the throttling is unclear, but the systems in these instances are reporting a "BD PROCHOT" CPU flag that indicates that some component inside the computer is running too hot, which results in the CPU throttling to decrease the temperatures inside the computer. Unfortunately, the throttling doesn't stop, as the 400MHz clock speed remains for some even after shutting down and rebooting the computer.

But, which component?

Normally, you'd hope for the computer temperatures to go down and have CPU return to normal speeds after the component that raised the flag stops overheating. But, in this case, it's not clear that any component actually is overheating. 

Some users did suggest the throttling stopped when disconnecting a Surface Dock or AC adapter, while others suggest antivirus software may be at fault. What may be the root of it all is a firmware update. One was recently released for the Surface Pro 6.

This wouldn't be the first time an update caused issues for Microsoft's machines. Just recently, Wi-Fi and Bluetooth drivers were hit with issues, and the Windows 10 May 2019 update has caused problems for the Surface Book 2.

A Microsoft spokesperson told TechRepublic, "We are aware of some customers reporting a scenario with their Surface Books where CPU speeds are slowed. We are quickly working to address via a firmware update."

Mark Knapp

Over the last several years, Mark has been tasked as a writer, an editor, and a manager, interacting with published content from all angles. He is intimately familiar with the editorial process from the inception of an article idea, through the iterative process, past publishing, and down the road into performance analysis.