I have an Ultra Flair 128GB that does the same thing, except if ran even longer (before it locks up), as it runs it gets slow and slower, it dips down to about 6MB/s when there is a high # of writes, but sustained writing of larger files does average about 8MB to 10MB/s.
- The OS is not updating. That is disabled and done manually.
- AV enabled or disabled makes no difference
- Malware apps not running but system scanned and confirmed clean
- Same behavior on rear port, front port, USB hub, and different system
In all cases removing the Ultra Flair and using a Sandisk Extreme USB3 instead, works fine without this slowdown.
It is slowing down as it gets hot and if left running hot it eventually locks up and can’t be accessed until removed, allowed to cool, then plugged back in. The only time it can achieve over 12MB/s is if it was sitting unused, then plugged in and a copy started before it warms up, and then only until it warms up, a minute or two at most.
I never expected 15 times faster than USB2 for writes, but I did expect it to be faster continuous writes than my 8+ year old USB2 flash drives which have dozens of times as many writes to them already.
This was all observed using the factory format. At one point I had nearly filled it and wanted reuse it for something else and found it was impossible to delete all the files in a timely manner because it kept locking up from heat, so I then reformatted it as FAT32. That made minimal to no difference, still slows down to similar sub-10MB/s speeds after a minute or two.
