An article from "The Guru of 3D"
"AMD acknowledges that Windows 11 is slower than Windows 10 on suitable AMD processors. This is due to issues with the L3 cache and the processor's thread distribution across cores. Microsoft and AMD are now working on fixes that will be available in October.
The L3 cache's latency is three times that of Windows 10. As a result, AMD cautions that applications that are sensitive to memory subsystem access time variances may operate slower than before. Sensitive applications may operate around three to five percent slower than they should. Certain programs, "such as those frequently used in esports," may perform 10 to 15% slower than they did on the previous OS.
The second issue is with CPPC2, which controls which threads are processed by which cores within the UEFI. With Windows 11, threads would no longer be processed automatically by the processor's fastest core. Performance degradation would be noticeable in particular for programs that rely on a single or a few threads. This issue would be most obvious in processors with eight or more cores and a TDP more than 65W.
While Windows updates are required for the L3 cache, AMD updates can resolve the CPPC2 issue. AMD has stated that both patches would be available in October. Affected users are recommended to continue using Windows 10 until then.
Windows 11 was released on Monday evening. On Tuesday, tweakers provided benchmarks for the new operating system. This already shown that the AMD CPU utilized in certain apps performed slower than the CPU used in Windows 10, although the differences were minimal in other applications."
