Microsoft has confirmed that some Surface Pro 6 and Surface Book 2 users have been affected by processor throttling following a recent firmware update. The processors of the ultra-slim devices throttle down to 400MHz and remain that way, even after shutdowns and restarts.
Surface Pro 6 and Surface Book 2 users have been posting information about the slowdown on Reddit for the past week. Today, Microsoft acknowledged the issue in a statement made to the website 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," a Microsoft spokesperson told the site.
For now, redditors have seemed to pinpoint the Intel CPU flag BD PROCHOT (bi-directional processor hot) as the culprit of the throttle lock. The flag tells the processor to throttle down in an attempt to keep the system temperature from overheating. However, the BD PROCHOT can be triggered by other components or peripherals, not just the CPU. Ideally, this works to prevent other components around the CPU from overheating due to the CPU’s thermal output. In this instance, BD PROCHOT is being activated even when CPU temperatures are low.
Microsoft's Surface PCs aren't the only computers to utilize BD PROCHOT, but a large number of complaints about those particular models have popped up lately.
There is currently no official fix to the problem, though some users have found the third party app, ThrottleStop, to be an effective workaround. It is important to note that one should be cautious when using third party applications to turn off system settings.