AMD warned last week that its chips are experiencing performance issues in Windows 11, and now Microsoft’s first update to its new OS has reportedly made the problems worse. TechPowerUp reports that it’s seeing much higher latency, which means worse performance, after the Windows 11 update went live yesterday.

AMD and Microsoft found two issues with Windows 11 on Ryzen processors. Windows 11 can cause L3 cache latency to triple, slowing performance by up to 15 percent in certain games. The second issue affects AMD’s preferred core technology, that shifts threads over to the fastest core on a processor. AMD says this second bug could impact performance on CPU-reliant tasks.

TechPowerUp measured the L3 cache latency on its Ryzen 7 2700X at around 10ns, and Windows 11 increased this to 17ns. “This was made much worse with the October 12 ‘Patch Tuesday’ update, driving up the latency to 31.9ns,” says TechPowerUp. That’s a huge jump, and the exact type of issue AMD warned about.

Patches for both of the Ryzen issues are coming before the end of the month, though. The L3 cache issue will likely be addressed next week by Microsoft, with rumors suggesting October 19th for a patch. The preferred core patch will be addressed by an AMD driver, which is expected to be delivered later this month and will hopefully be available on Windows Update as soon as it’s released.

It’s still surprising to see Windows 11 ship with these issues, especially when Microsoft has limited the amount of supported processors for this new OS. Bugs always happen with new OS releases, but such an obvious performance impact on key CPUs should have been picked up during the months of public beta testing. Either way, it’s encouraging to see this will be fixed very soon so those suffering from worse performance won’t have to wait too much longer for a patch.