Windows 11 update warning: AMD users are reporting sudden performance drops

If your computer is packing an AMD Ryzen CPU, you should probably hold off upgrading to Windows 11.

This is because in the 48 hours since Microsoft unleashed Windows 11 to supported computers, AMD has updated its support site to warn users of two issues facing those with Ryzen CPUs.

Neither are showstoppers, but both will impact performance enough to ensure that those with Ryzen technology would be better off sticking with Windows 10 until software updates are issued to resolve the problems.

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The first is that Windows 11 is apparently causing L3 cache latency to triple. In real terms that means you can expect a performance drop of 3 to 5% in most impacted applications, but some games could see that hit increase to as much as 10 to 15%. AMD notes that these “outliers” are predominantly “in games commonly used for eSports”, which is the last thing you want when going into a tournament.

The second issue is with AMD’s “prefered core” technology. Normally, this moves threads to the fastest core on a processor, but it doesn’t seem to be doing its job properly in Windows 11, which means that “applications sensitive to the performance of one or a few CPU threads may exhibit reduced performance.” AMD says that this is likely to be more noticeable if you have a CPU with more than eight cores with more than 65W TDP.

Slipping through the net 

The good news is that neither problem is likely to be around for long, with both bugs expected to be fixed later this month via a software update.

But it’s perhaps surprising that both of these issues have only just been caught now. After all, Windows 11 builds have been available to Insiders since June, and Microsoft was boasting of the preview’s popularity on a call to investors back in July. “More people have downloaded our early builds than any other Windows release or update in the history of our Insider program,” CEO Satya Nadella said at the time. 

You would have hoped that the problems would have been spotted in advance therefore, and some warning ahead of Windows 11’s release on Tuesday would certainly have been welcome. Now Ryzen owners who have already taken the plunge will have to decide whether to go through the awkward process of downgrading to Windows 10, or just to stick it out until a fix arrives. 

Windows 11 will automatically be delivered via Windows Update for compatible Windows 10 users, but if you don’t want to wait, you can skip the queue and download the updater directly from Microsoft.