If you’re running Windows 11 on an AMD Ryzen chip, brace yourself for slight performance dips. AMD says it’s uncovered a mysterious issue in its processors that can trigger “reduced performance in certain applications” on Windows 11, which launched on Tuesday.
The chip maker’s support document indicates that all AMD processors officially compatible with Windows 11 are affected. For consumers, these chips go back to 2018's Ryzen 2000 series.
One of the discovered problems can cause the L3 cache in AMD chips to potentially increase the latency by three times. Slowing the L3 memory bank can thus drag down the access times for certain applications. “Expected performance impact of 3-5% in affected applications,” AMD wrote in the support document. “10-15% outliers possible in games commonly used for eSports.”
The second issue deals with the chips' “UEFI CPPC2" system, which can communicate with the OS about which CPU cores are best capable of achieving a high boost speed for a given programming task. For some reason, the UEFI CPPC2 won’t always “preferentially schedule threads on a processor’s fastest core” while running Windows 11, AMD says. As a result, the problem can cause performance to slow, especially for single-threaded programs.
“Applications sensitive to the performance of one or a few CPU threads may exhibit reduced performance,” the company added. “Performance impact may be more detectable in >8-core processors above 65W TDP.”
It's probably best to wait on installing Windows 11 until the bugs are ironed out. Fortunately, AMD and Microsoft are preparing fixes for both problems, which should arrive later this month.