Very slow SD card access since recent update to build 22581 - resolved

Copper Contributor

my laptop has been running Win 11 Beta program for several months. I use a 1TB SD card for additional local storage and its been great. Since the recent update to 22581 my read speeds on the SD card are slow and seem to max out 33.3 MB/s. The card is rated up to 120Mb/S (UHS-I / A1 / Class 10)

Verified I have correct drivers from MS and from Manufacturer. I tried temporary antivirus removal, none of which had any impacts.

Any suggestions on further steps? should I send MS a bug report?

slow SD card.jpg


update 4/9/2022

received build 22593 last night, SD card issues are resolved now

2 Replies


Either it is related to write endurance, lack of drivers, or the bootloader not supporting a driver from another major revision of Windows.


Modify the bootloader with this Batch File (.bat) to support legacy peripherals (also try disabling "ABOVE 4G MIMO" in UEFI/BIOS.)

REM Start Menu -> Run -> taskmgr -> File -> Run new task -> %SystemRoot%\System32\cmd.exe -> Check: Create this task with administrative privileges -> OK
REM NOTE: If you cannot find the correct entry, first run this: BCDEDIT /ENUM and replace {current} with {default} or whatever is listed below
REM Windows Boot Loader
REM -------------------
REM identifier              {current}
REM device                  partition=C:

NOTE: One way around it which may not work, given there is no TRIM command for SD Cards, is to run the CLEAN command on the drive in DISKPART, and then reformat it (but you lose everything on the SD Card in the process. All you're really doing is wiping out the entire filesystem on that drive. Sometimes that can fix a filesystem issue with USB drives and SD Cards, but it's not always the case.) It's way easier to do other things first like modify the bootloader, or search for Motherboard drivers for the SD Card Controller. For instance, some SDcard readers require drivers to be installed which may not come with Windows 10/11:

Thanks for your response, can you please explain what that MOVE command is for? call me internet paranoid but I like to understand what a given script does before execution, especially as admin. The BCDEDIT help I am onboard with and I ran that bit and restarted - no improvement so I would like to understand what the MOVE does.


I should clarify that my laptop is less than 6 months old and this was performing well, up until very recently.