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AMD has announced that some of its processors have taken a performance hit on Windows 11 so much so that it’s normal to see a 3-5% impact and up to 10-15% in some less common situations. Luckily, those impacted by the issue should receive a patch through Windows that addresses the issue soon; the company is currently working on a fix and expects to push it this month.
According to Tom’s Hardware, the issue affects all AMD processors that are supported by Windows 11 including Ryzen, AMD EPYC, and Athlon branded processors.
The issue mentioned in the opening paragraph is caused by functional L3 cache latency which has increased by around three times on affected hardware. The programs that will suffer include those sensitive to memory subsystem access times. AMD noted another problem too, explaining that UEFI Collaborative Processor Performance Control (CPPC2) may not schedule threads on the processor’s fastest core preferentially.
Regarding the latter issue, applications sensitive to the performance of one or a few CPU threads will see a performance hit. The issue will be more noticeable on greater than 8-core processors that operate at over 65W. This issue should also be fixed this month.
Despite Windows 11 being considered ready for public use, it is being rolled out in waves to Windows 10 users so that issues like this can be fixed before everybody is upgraded. If you’d like to get Windows 11 right now, you can do so with the Microsoft Installation Assistant.