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.
The second bug is related to an AMD processor feature that tries to use your fastest individual CPU cores when running lightly threaded tasks rather than treating all cores the same. AMD doesn’t put a number on this one but says the problem “may be more detectable” in processors with eight or more cores and a 65 W or higher TDP. This would include most 2000, 3000, 4000, and 5000-series Ryzen 7 and Ryzen 9 desktop CPUs and APUs. AMD says that a “software update,” not a Windows update, will be released to fix the problem later in October, so you may need to install new AMD chipset drivers or some other software to get the fix.
The AMD Ryzen issues are separate from performance slowdowns caused by some of Windows’ virtualization-based security features. In particular, testing by outlets like Tom’s Hardware has shown that the Memory Integrity security feature can reduce performance by a few percentage points in some games and general computing tasks, though the results vary widely based on the software you’re using and the processor you have. The feature is included in both Windows 10 and Windows 11 but is disabled by default in both operating systems for all but the most recent laptops and desktops sold by major PC makers.