After Microsoft officially released Windows 11 on October 5, many users like the Windows 11 new interface and features. At the same time, they have encountered some problems using Windows 11. They encountered memory usage problems, including the interface freezing and the game frame rate dropping after upgrading to Windows 11. But Windows 11 fixed this problem via updates. However, there are still many bugs left. Recently, a large number of reports said the NVMe SSDs speed using Windows 11 is reduced.

According to reports, with the support of CrystalDiskMark and AS-SSD (a popular benchmarking application for PC drives), the performance of Windows 11 may be several times slower than NVMe drives in some cases. This problem particularly affects random write performance. Although most other indicators are not affected, the difference is still very significant. The image below is comparison of the same SSD running Windows 10 and Windows 11.

The reason why SSD performance becomes might be the virtualization-based security (VBS), but this did not make up for all the differences between Windows 10 and Windows 11.
It seems that this issue is caused by the drivers from Windows 11. If you run a benchmark test on the secondary drive, the result will be consistent with the advertised value of the SSD. The image is the comparison between two 2TB Samsung 980 Pro NVMe SSDs speed on the same machine.

Another recent report said that the latest Windows 11 update version 22000.348 (KB5007262) slightly improves SSD performance, although it is far from the performance on Windows 10. A Microsoft engineer on Reddit admitted this problem.
Windows 11 has lots of other issues after the official release, such as poor performance of AMD processors and so on. Anyway, these issues have been fixed one by one, so we can only hope that Microsoft can also fix the slow NVMe SSDs speed at this time.