Windows 11's first cumulative update makes AMD CPU issues worse, but a fix is coming

AMD Ryzen 9 3900X
AMD Ryzen 9 3900X (Image credit: Rich Edmonds / Windows Central)

What you need to know

  • The first cumulative update for Windows 11 appears to make an issue with AMD processors worse.
  • AMD and Microsoft previously identified two issues related to AMD processors, one of which is worsened by the recent Windows update.
  • Fixes for these issues will reportedly roll out on October 19 and October 21, 2021.

Update October 15, 2021 at 2:15 p.m. ET: The latest Windows 11 Release Preview and Beta Channel build has addressed the L3 caching issue.

Shortly after the launch of Windows 11, two issues were discovered that affected the performance of AMD processors. One problem caused a performance drop of 10-15%. Those issues got even worse following the first cumulative update to Windows 11, according to a report by TechPowerUp. People with affected AMD systems may want to wait to upgrade to Windows 11 as fixes for these issues are expected later this month.

One of the previously discovered issues can cause L3 cache latency to increase dramatically. The other issue involves AMD's preferred core technology, which shifts threads to the fastest core on a processor. TechPowerUp's findings relate to the first issue.

"In our own testing, a Ryzen 7 2700X "Pinnacle Ridge" processor, which typically posts an L3 cache latency of 10 ns, was tested to show a latency of 17 ns," said TechPowerUp. "This was made much worse with the October 12 "patch Tuesday" update, driving up the latency to 31.9 ns."

AMD reportedly shared a statement on social media, which has since appeared on Reddit, about fixes for these issues. A patch for the preferred core bug will come in an AMD driver update on October 21, 2021, according to the post. A Windows Update said to be on the way for October 19, 2021 will address the L3 cache latency issue.

Sean Endicott
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Sean Endicott brings nearly a decade of experience covering Microsoft and Windows news to Windows Central. He joined our team in 2017 as an app reviewer and now heads up our day-to-day news coverage. If you have a news tip or an app to review, hit him up at