M1 Macbook Pro SD card reader super slow or getting errors when copying

Just found this other thread where another user is having issues with the same type card (Vendor ID & DeviceID as yours):

 SD Card Reader Only Works if Inserted at … - Apple Community

Here is a MacRumors thread where a user is trying to perform some experiments to identify which cards are working & which are not (they had multiple SanDisk SD Cards....some were fine, others not):

https://forums.macrumors.com/threads/macbook-pro-m1-2021-sd-card-test-report-collaboration.2327880/

And I stumbled across this site which purports to have software developed by Tuxera to properly format the SD Cards. Very interesting since I can see this could be part of the problem since I know some similar occurs with SSDs as well. Tuxera has been around for years supplying third party file system drivers to allow access to file systems that a particular OS does not natively support. I have not vetted this software since I just found it.

https://www.sdcard.org/downloads/formatter/

I do know that macOS definitely can have fits if a drive, partition, or file system is not what it expects.

I've seen other people report issues with the built-in SD card slot while using an external SD Card Reader works. I would suggest going with whatever works.

Have you tried disconnecting all other external devices to see if that makes any difference? Sometimes other devices can cause a compatibility issue.

Adeski wrote:

Thanks for getting back to me. Nothing else plugged in. Sounds like a fault with the hardware, but a number of people seem to have this fault.

I'm always wary & skeptical of any specialized integrated options like an SD Card slot, since there are so many different types of SD Cards and they keep changing & evolving where that particular slot may be incompatible with a newer style card. An external SD Card reader is always the best option since it can be easily be replaced or upgraded if necessary, but a built-in card reader is stuck with whatever features & abilities it had when sold.

Not sure what Link Speed means and why it is OFF ?

Link speed is the speed (aka transfer rate) that the SD Card and macOS agree upon to use. They must negotiate this between them to pick an acceptable rate that both devices can handle & understand. Being listed as Off is probably due to the SD Card & macOS not working correctly together assuming macOS actually populates that field (I cannot make that assumption since I've seen macOS report some things incorrectly with the M-series Macs).

Unfortunately I cannot say whether your SanDisk SD Card is even compatible with the M-series Mac's built-in SD Card slot. Like I said earlier, there are a lot of different style SD Cards out there making it very difficult to know for certain if a particular SD Card will work with a particular SD Card reader. I'm not sure if Apple even lists which SD Card specifications it can handle.

Not all SD Cards are compatible with all devices. Again why I think an external card reader is best, so use what works.