New Windows 11 bug is slowing down some devices by up to 25% and piling more misery on Microsoft

Angry man screaming at laptop
(Image credit: Shutterstock / ra2 studio)

A Windows 11 bug which is seriously slowing down processors has been discovered in test versions of the OS – although Microsoft has said it’s on the case, so it should be fixed soon enough, with any luck.

The bug is present in preview builds of Windows 11 24H2 – the next big update for the operating system – and it’s caused by the Cross-Device Experience Host going wrong somewhere.

Neowin spotted that a number of users have said their CPU performance has been impacted – substantially in some cases – by the process. As the name suggests, the Cross-Device Experience Host (CDEH) is the functionality that links your smartphone and Windows PC to make it easier to achieve tasks like sharing photos from your phone to the desktop. (This runs alongside the existing Phone Link app, by the way).

There are reports of the bug in various places, including Microsoft’s own Feedback Hub and its Answers.com support forum. The slowdown reported varies, mind, with some folks saying that the CDEH process is eating something like 5% to 10% of their CPU – still pretty bad – but others are claiming 15% to 20% slowdowns, or even 25% in one case.

For the CPU to be losing that level of resources to a misfiring process running in the background of Windows 11 is a pretty dire situation, frankly.

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

Gentleman replied on the Feedback Hub: “Appreciate your patience, we’ve identified the cause and are working on a fix.”

Microsoft presenting Surface Laptop and Surface Pro devices.

(Image credit: Microsoft)

Analysis: bad timing

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

We’re also not 100% sure if the CPU draining glitch might be present with Copilot+ PCs, but it won’t be as far as we’re aware. Those AI PCs launch today, June 18, with a 24H2 build on board – but not the finished one. There are still a good deal of features missing from the version of 24H2 that debuts with Copilot+ PCs, and the full suite of features won’t debut until later this year when the 24H2 update rolls out to all Windows 11 devices – and this is when CDEH comes into play, we assume.

At any rate, the only concern for Windows 11 users broadly is that Microsoft gets a fix in place, which it surely will by the time the 24H2 update is rumored to land (around September 2024). Our worry would be if the fix isn’t implemented properly, and there are still some issues left around this CDEH slowdown – but hopefully that won’t happen. If it did, it wouldn’t be the first time a bug fix applied by Microsoft didn’t fully work, mind – and this would be a particularly bad one to slip through the net.

On an overall level, the timing of this revelation isn’t great. As mentioned, the launch of Copilot+ PCs – Microsoft’s new era of AI-supercharged computing – is happening right now, and Microsoft has just pulled its kingpin AI feature – Recall – from that launch following a whirlwind of controversy, and now we have a bug in Windows 11 which is causing some CPUs to run like treacle (well, not quite, but markedly sluggishly in some cases).

The future of computing suddenly looks a bit chaotic, going by the past week – and Microsoft will need to get its act together sharpish.

You might also like...

TOPICS

Darren is a freelancer writing news and features for TechRadar (and occasionally T3) across a broad range of computing topics including CPUs, GPUs, various other hardware, VPNs, antivirus and more. He has written about tech for the best part of three decades, and writes books in his spare time (his debut novel - 'I Know What You Did Last Supper' - was published by Hachette UK in 2013).

Read more
Windows fail
It looks like Microsoft might have broken Windows 11 24H2 again as performance plummets with Intel's latest CPUs
A man getting angry with his laptop.
Windows 11 bug deletes Copilot from the OS – is this the first glitch ever some users will be happy to encounter?
A Microsoft Surface Pro 11 on a desk
Microsoft in 2024: year in review
Angry business man screaming on laptop
Finding Windows 11 sluggish when you’re working with files and folders? You’re not alone – and it’s high time for Microsoft to sort out File Explorer
Upset young man plays computer games at home.
Windows 11 24H2 is in danger of becoming hated by gamers
A finger touching a screen showing the Windows 11 logo
5 reasons why I’m finally upgrading to Windows 11 in January
Latest in Windows
A woman sitting in a chair looking at a Windows 11 laptop
It looks like Microsoft might have thought better about banishing Copilot AI shortcut from Windows 11
Using Zipped files and folders in Windows 11
Windows 11 should soon be faster at extracting files from compressed ZIPs – and it’s about time, frankly
Xbox Wireless Controller
Microsoft is adding a powerful new feature for using Xbox controllers with Windows 11
Woman disgusted by her laptop
Embarrassing Windows 11 bug that deleted Copilot app is now fixed – but will anyone outside of Microsoft care?
Student sat at a desk with a laptop in a dormitory looking at a mobile phone
Windows 11 could eventually help you understand how fast your PC is - as well as offer tips for making your PC or laptop faster for free
Windows 10
Microsoft gets into the spam game by again emailing Windows 10 users to prod them to upgrade to Windows 11 – is the nagging going too far now?
Latest in News
Microsoft
"Another pair of eyes" - Microsoft launches all-new Security Copilot Agents to give security teams the upper hand
Hatch Restore 3 in Putty
You can finally start your day with The Office theme song, and I couldn't be more excited
Cassian Andor looking nervously over his shoulder in Andor season 2
New Andor season 2 trailer has got Star Wars fans asking the same question – and it includes an ominous call back to Rogue One's official teaser
Ncuti Gatwa as The Fifteenth Doctor in Doctor Who
Disney+ drops new trailer for Doctor Who season 2 that promises an epic adventure across time and space
23andMe
23andMe is bankrupt and about to sell your DNA, here's how to stop that from happening
A phone showing a ChatGPT app error message
ChatGPT was down for many – here's what happened