AMD warned last week that their chips were experiencing performance problems in Windows 11. Microsoft's first OS update has apparently made matters worse. TechPowerUp reports that it is experiencing much higher latency which, in turn, means poorer performance after the Windows 11 update was released yesterday.
Microsoft and AMD discovered two problems with Windows 11 on Ryzen processors. L3 cache latency can triple in Windows 11, which can lead to performance slowing down by as much as 15% for certain games. This second issue is related to AMD's preferred core technology. It shifts threads to the fastest core of a processor. AMD claims that this second bug could affect performance for CPU-reliant tasks.
Yesterday was the first Windows 11 update
TechPowerUp measured L3 cache latency for its Ryzen 7 2700X at approximately 10ns. Windows 11 raised this to 17ns. TechPowerUp says that the October 12 Patch Tuesday update made the latency even worse, increasing it to 31.9ns. This is a significant jump and exactly the type of issue AMD warned you about.
However, patches for both Ryzen issues will be available before the end the month. Microsoft will likely address the L3 cache issue next week. Rumours suggest that a patch for October 19th. An AMD driver will address the preferred core patch. It is expected that it will be delivered in the latter part of this month. Windows Update will hopefully have it available as soon as possible.
These issues are still quite surprising, given that Windows 11 ships with a limited number of processors. While bugs are always present with new OS releases there is no denying that these issues have an impact on the performance of key CPUs. This should have been noticed during months of beta testing. It is encouraging to see that this issue will be addressed quickly so people suffering from poor performance don't have to wait too long for a patch.