I use my laptop to transfer camera cards to SSDS and have notice the I don't get consistent speeds. The same 9GB using the exact same ports and SSDs will some times take 45 secs or 3 minutes. If I retry a few minutes later with everything the same it will drop back to 45 secs. Is there something wrong with the IO board?
MacBook Pro 16″, macOS 12.1
Those little SD card certainly are convenient for transferring data from time-to-time. But they are complex creatures inside, and their performance (as you observed) is wildly variable. There is likely nothing wrong anywhere.
If you need a speedy (or even consistent, or strongly reliable) performance, you are not using the correct media for that. SD cards are for convenience.
If you are losing sleep over this, you could run the Apple Diagnostics.
Remember that "no fault found" means that in the very small amount of time and the very limited test performed, no gross faults were detected. That is not the same as "all is well".
There is no known pattern of USB interfaces being flaky in the way you describe -- except ones attributable to Bad cables.
But I thought you were complaining about device plugged in directly -- no cables involved.
This has occurred with other cards such as CFast and XQD so I dont think its card related
Diagnostics came up clean. This may seem like minor issue but when transferring close to a terabyte of data the difference is 3hours vs. 20 mins.
Erratic data speed through USB-C ports
