Speed variation on ssd drive

Hi. My first post, so hoping for some advice. I recently purchased 2 ITB Sandisk portable ssd drives.
I transferred files (raw files/photos) to one of the drives and got a transfer speed from my Windows 10 PC SSD drive of 270-300 MB/sec. Transferring the exact same files to the other sandisk ssd resulted in a speed of around 30-0MB/sec. I’m unsure as to why the transfer speed varies so much between the same ssd drives. Thanks in advance.
Paul

Hi @Guitarman70 ,
Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for best assistance and troubleshooting: