I checked the countermeasure patch to eliminate Ryzen's performance degradation in the Windows 11 environment

AMD announced on October 6th that performance degradation will occur in the Windows 11 environment when using Ryzen processors, but distribution of patches corresponding to this has also started on the normal channel of Windows 11. .

There are two problems with this, one is that the latency of the L3 cache is about three times that of Windows 10, and the other is that CPPC2 does not prioritize priority cores correctly. The former was supposed to be fixed by Microsoft, and the latter by AMD. The former, the Windows insider channel, had already released a patch, but on October 22nd, KB5006746 began distribution on the normal channel and is already installable (Photo01).

On the other hand, CPPC2 support is also available from AMD. From the company's driver download page, select "Chipset" → "Socket AM4" → the desired chipset (I chose "X570") to open the download page, where you can download Chipset Driver 3.10.08.506.

Alright, let's do a quick test. The processor is Ryzen 9 5950X, but before and after applying KB5006746 and CPPC2 Driver, I checked the Latency using Sandra 2021 Cache & Memory Latency Global Data Memory: In-Page Random ( Photo02). When KB5006746 is applied, for some reason the latency tends to increase slightly in the L1 → L2 area, but it can be seen that the latency is clearly reduced in the L3 area (4MB to 32MB).

So, if you are using Windows 11 on Ryzen, we recommend applying KB5006746 and UEFI CPP2 Driver.