USB - Slower transfer data

Every time I connect on my MacBook Pro (Mid 2014) any usb storage the data transfer is slower than usual both in upload or download. For instance, if I try to download 1giga, it will take around 1hour (the system bar start show a slow download, than seems accelerate but than is slowly again, this happen every time). This problem happen with any usb storage key (formatted in EX FAT or MS-DOS fat32)

I tried already many solution:

- reset PRAM/NVRAM

- reset Reset SMC

- macOS Recovery reinstalling the OS system on line

- scans with malwarebytes (no virus or malware result)

- I have also waited for the last system upload but nothing happened

What could I do? please help me!