Windows 11 slows down Ryzen CPUs by up to 15% but a fix is coming, says AMD

AMD has informed users that the Windows 11 update causes performance issues with all Ryzen CPUs, but the company is working with Microsoft to issue a fix. Here’s everything you need to know about this issue affecting AMD CPUs after the Windows 11 update.

Unfortunately for users running on affected AMD processors on Windows 11, there’s no easy fix for the issues until AMD and Microsoft release their fixes later this month.

The Windows 11 update arrived earlier this week and like every new major software release, bugs and issues have begun to show up. AMD has informed users that the Windows 11 update has negatively impacted all of its Ryzen processors, causing a drop in performance while using some applications on Windows 11. However, the company and Microsoft are already working on software fixes that should arrive later this month, the company has stated.

The semiconductor designer explained in a knowledge base (KB) article that the company and Microsoft have determined that compatible AMD processors may exhibit “reduced performance” in certain applications when running Windows 11. It is worth noting that the issue impacts all Zen+, Zen 2 and Zen 3 Ryzen CPUs that are supported on Windows 11. If users are running Windows 11 on the Ryzen 5000, Ryzen 4000, Ryzen 3000 and Ryzen 2000 series, they will see performance drops. Users can check the entire list of affected CPUs here.

According to AMD, some applications that are sensitive to memory subsystem access time could be impacted by the Windows 11 update, seeing up to 3 times increased L3 cache latency. Affected applications could see a performance drop of 3 to 5 percent, while the figure could be higher at 10 to 15 percent for “games commonly used for eSports”, according to the company. However, the good news is that Microsoft is expected to address this issue with a Windows update that is expected to arrive in October 2021.

Similarly, the company's UEFI CPPC2 (or “preferred core”) feature may also experience issues, due to the Windows 11 update which may impact some processes on AMD chips that are running on eight or more cores with a 65W or higher TDP rating. The preferred core feature allows the system to quickly assign AMD's most powerful cores for single-threaded applications, as Tom's Hardware explains. These issues will be addressed in a separate software update from AMD, which is also expected later this month.

Unfortunately for users running on affected processors, there's no easy fix for the issues until AMD and Microsoft release their fixes later this month. “AMD and Microsoft are actively investigating these known issues for resolution via software updates,” the company states in its advisory. “In the interim, customers using compatible AMD processors affected by these issues may continue to use a supported version of Windows 10,” it adds, which might be an option for those users who have recently installed the Windows 11 update and still have the option to “roll back” to Windows 10.