A new Windows 11 bug is slowing down some devices by up to 25% and causing even more woes for Microsoft

Windows 11 is currently experiencing a testing bug that is seriously slowing down processors – although Microsoft has stated that this is happening, so with any luck it should be fixed soon.

The bug occurs in test builds of Windows 11 24H2 – the next major update to the operating system – and is caused by a bug somewhere in the Cross-Device Experience Host.

Neowin noted that many users found that this process impacted – in some cases significantly – the performance of their processor. As the name suggests, Cross-Device Experience Host (CDEH) is a feature that connects your smartphone to your Windows PC to make tasks like sharing photos from your phone to your PC easier. (By the way, this works alongside the existing Phone Link app).

There are reports of the bug in various places, including the Microsoft Feedback Center and the Answers.com support forum. Reported slowdowns vary however, with some claiming the CDEH process consumes between 5% and 10% of the CPU – still quite good – but others claiming slowdowns ranging from 15% to 20%, and in one case even 25%.

Honestly, losing this level of CPU resources due to a Windows 11 background process not starting properly is quite tragic.

Microsoft’s Jen Gentleman, who is part of the Windows testing team, confirmed that there is an issue here and work is underway to fix it.

Gentleman replied to the Feedback Hub: “Thank you for your patience, we have identified the cause and are working to resolve it.”

Microsoft presents Surface Laptop and Surface Pro devices.

(Image source: Microsoft)

Analysis: bad timing

The good news is that a fix is coming – and remember that this bug doesn’t affect you yet unless you’re a tester. CDEH functionality is still in preview (in the unreleased 24H2 update) and has not yet been rolled out to all Windows 11 users, but of course it will be later this year.

We’re also not 100% sure if the CPU exhaustion bug may be present in Copilot+ computers, but from what we know it won’t be that big of a deal. These AI computers will launch today, June 18, with a 24H2 version – but not ready. There are still many features missing from the 24H2 version that debuts on Copilot+ machines, and the full feature set won’t debut until later this year when the 24H2 update rolls out to all Windows 11 devices – which is when we assume CDEH comes into play.

In any case, the only concern for Windows 11 users is that Microsoft will receive a fix, which will certainly happen by the time the 24H2 update rumors emerge (around September 2024). We’d be concerned if the fix wasn’t implemented correctly and there were still some CDEH slowdown issues – but let’s hope that won’t be the case. If this happened, it wouldn’t be the first time Microsoft’s bug fix didn’t fully work – and it would be especially bad to get through the network.

Overall, the timing of this revelation isn’t very good. As mentioned, the launch of Copilot+ computers – Microsoft’s new era of AI-powered computers – is happening right now, and Microsoft has just pulled its Kingpin AI feature – Recall – from that launch after a whirlwind of controversy, and now we have a bug in Windows 11 that causes, that some processors run like molasses (well, not really, but noticeably slow in some cases).

Last week, the future of computing suddenly seemed a bit chaotic, and Microsoft was going to have to get its act together.