I have about 3.2 TB of data I want to put onto a 4TB SSD. I made 1 copy of this data to an enclosed desktop 4TB SSD with a self powered enclosure. Now I want to transfer this data to another External SSD, but a Crucial X6. The file transfer started at over the rate 200mb/ps but when the data reached the 1.2TB threshold, now everything is transferring no more than 50mb/ps. The Crucial is formatted exFAT and the source is NTFS. I used Windows - which transferred slower even when using robocopy - and I am using linux rsync and gcp and still can't get any better transfer rates.
Ideas? Should I buy another brand or try a different format for the destination?