AMD Confirms Windows 11 Performance Hit, Patches on the Way

If you’re contemplating upgrading to Windows 11 on an AMD system, you may want to hold off just a bit. The semiconductor design firm has confirmed that Windows 11 performance is a bit lower on Ryzen CPUs than under Windows 10 right now.

AMD has published a new support article, PA-400, detailing the problem. The company is suffering two regressions under Windows 11. First, “measured and functional L3 cache latency may increase by 3x.” This is said to cause a 3-5 percent performance hit in most affected applications, with outliers of up to 15 percent in some eSports titles.

Second, AMD’s UEFI CPPC2 driver “may not preferentially schedule threads on a processor’s fastest core.” CPPC2 stands for Collaborative Power and Performance,” and its part of how the CPU communicates with the operating system. We know AMD uses CPPC2 to communicate with the OS regarding which CPU cores are preferred for boosting in both Windows 10 and Windows 11. It seems the version of this software that runs under Windows 11 isn’t working quite right.

AMD is warning that the performance hit may be more detectable in chips with 8 or more cores and a TDP above 65W, which basically covers the Ryzen 9 3900X/5900X and 3950X/5950X. The company doesn’t state what performance impact this second issue causes, but it’s not exactly unheard of for operating systems to have teething issues.

There’s no firm timeline on when fixes will be available for either bug, but AMD is promising they’ll be ready this month. This issue is separate from the performance-impacting security features that are baked into Windows 11, which impact AMD Zen performance by 4-5 percent if left enabled on an OEM system or turned on by an enthusiast. While these two issues are unrelated, the net effect of them knocks most of a generation’s worth of improvement off AMD’s CPU cores. Enthusiasts will want to be careful when using OEM PCs, both as far as driver updates and underlying security configurations.

At the same time, it’s not unusual for a brand-new OS to have some teething problems, so this isn’t likely to represent some kind of long-term referendum on Windows 11’s gaming performance. As we’ve covered, Windows 11 is a bit more ‘meh’ than some of Microsoft’s previous releases. Gamers don’t need to be in any hurry to jump for the new OS, and while there’s no reason to specifically downgrade to Windows 10 there’s no great reason to upgrade to Windows 11, either.

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