https://arstechnica.com/gadgets/2021/10/windows-11-bug-could-reduce-ryzen-cpu-performance-by-up-to-15-amd-says/

Most people shouldn't rush out to install brand-new operating system versions on day one, and Windows 11 is no exception to that rule. AMD has published information about a pair of bugs that can reduce performance for Ryzen processors running Windows 11 by as much as 15 percent, though how much slowdown you observe will vary based on what you're doing and the CPU you're using. AMD expects both bugs to be fixed later this month.

The first issue AMD has identified increases L3 cache latency by up to three times, affecting apps that rely on fast memory performance. AMD says that most affected apps will slow down by between 3 and 5 percent but that some "games commonly used for eSports" could see dips of between 10 and 15 percent. AMD says that a Windows update will fix this issue later this month, so as long as you're checking for and installing Windows updates regularly, you won't need to do anything special to resolve the problem.