Copying 258Mb to a Corsair formatted NTFS starts fast then slows dramatically to 339kB/sec at the end, 20 minutes later. These are USB3 sticks on USB3 ports on my W530 Thinkpad. After reading the posts I formatted the 35Gb Corsair with ext4 and now it isn't seen at all on neither of my Ubuntu 16.4 Ubuntu machines. The only way I can copy seems to be using Deja'dup to external HDDs or by burning DVDs. I say "seems" as I have not tried a restore yet. Anyone have any ideas? Are there any drivers that I can download. I'm trying to hang in there until a new machine hopefully arrives in a month or so - Thanks - Garoolgan
dmesg
(type this command into a terminal) a few seconds after plugging in your USB sticks? If any errors occurred, they should be visible there. Anyway, a slowdown in USB write speed is generally a normal thing, as the real maximum write speed is the one you experience in the end, whereas the quick start is due to caching the data to write in RAM. I do agree that USB 3 should support faster speed than 400kB/s though, at least several MB/s (compare e.g. tomshardware.com/reviews/usb-3.0-thumb-drive-review,3477-2.html)