The problem with SSD slowdown in Windows 11 has its roots in ancient times, as the first reports about it appeared back in July 2021. In December, Microsoft released a fix for the problem, but it did not completely fix it. In February 2022, after the release of another patch, the error seemed to be fixed, but with the release of a major Windows 11 update called Moment 2 in March 2023, the problem reappeared. And it looks like Microsoft has found it Solution.
In March 2023, many Windows 11 users started complaining that their NVMe SSDs were running much slower than they should. As it turned out, the Moment 2 OS update (specifically KB5023706) contained a bug that caused many SSDs to run at half their normal speed. And it was only with yesterday’s patch release KB5029263 that Microsoft apparently fixed the SSD problem in Windows 11.
There are no references to the issue in the release notes for the new Windows 11 cumulative update, however many affected users are reporting that their SSDs are running at full speed again, with some still reporting a drop in performance of their SSDs. The distrust of users is also related to the lack of any information from Microsoft.
Microsoft has never publicly commented on the SSD slowdown bug in Windows 11, but appears to have been working on a fix in the background.