Read on Win 11's SSD issue from sammobile and extremetech:
Microsoft’s latest operating system, Windows 11, seems to be causing severe NVMe SSD performance losses, as reported by a number of PC users on several support threads. Various SSD models from different brands are affected by this problem. Samsung’s NVMe drives aren’t excluded, and this appears to be true for both PCIe Gen 4 and Gen 3 SSDs.
A Microsoft forum user going by the name
PleasedPen25317 shared a couple of CrystalDiskMark benchmarks for the Samsung 980 Pro SSD, and the results — seen in the image gallery below — speak for themselves. There’s a massive performance loss in random write speeds, and interestingly enough,
PleasedPen25317 found that the issue affects NVMe drives and partitions that have Windows 11 installed, regardless of whether or not said Windows installation is loaded.
A Samsung 970 Evo Plus user reports via reddit that random write speeds in benchmarks are roughly halved in Windows 11 compared to Windows 10. The 980 Pro isn’t the only Samsung drive affected. Other reports (via
Neowin) reveal that different NVMe drives/brands can exhibit other issues, such as reduced input/output operations per second.
This problem isn’t entirely new, interestingly enough. It has been brought to light by Windows 11 beta testers since before the public release of the OS, but it seemingly persists. Another reddit user posted similar performance losses in the AS SSD benchmark using the Samsung 980 NVMe drive in Windows 11 roughly three months ago (via
XDA-Developers). Because this problem seemingly affects NVMe SSD models from different brands, a fix is most likely out of Samsung’s reach, and customers will probably have to wait for Microsoft to address it.
Microsoft has figured out what is causing this issue, as revealed in a
blog post, noting it will be resolved in Windows Preview build KB5007262. Instead of the issue being related to Windows drivers, it’s due to the enabling of the USN journal on the C:/ drive, which keeps track of changes made to the drive and is always enabled. According to Microsoft, the fix “Addresses an issue that affects the performance of all disks (NVMe, SSD, hardisk) on Windows 11 by performing unnecessary actions each time a write operation occurs.” This would explain why some users were seeing it on their primary drive, but not on secondary volumes. It’s not clear what is causing these “unnecessary actions,” but thankfully it’ll be patched soon. Microsoft notes there will only be security updates this moth as opposed to bug fixes like this, so we expect this to roll out sometime in January of 2022.