I’ve had this issue since the first day I started using linux about 15 years ago. Always the same issue, transfers start fine and slows down to a crawl, only on USB sticks.
The USB sticks are fine, I can make bootable sticks in five minutes but if I copy a file of similar size to them is half an hour and then five to ten more minutes waiting to be able to safely remove the drive.
There are dozens of forum posts, some blaming the drives, others the GUI, dirty buffers, outdated kernels, fastboot for some reason. Others marked as solved without a solution because it magically solved itself.
This is the bit that interests me. Are you saying if you e.g. restore an ISO image, you can write to the USB a lot faster than when you copy files? If so, that would either point to a filesystem driver issue or an issue with the tool being used to copy files. Or something else interceding such as AV or selinux.
I could try to copy files using the command line and see what happens. Sigh, I’ll have to figure out where it mounts the usb for that.
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