Generally the sorting speed is dependent on disk I/O. Where are the files stored when you experience this issue? If it is an external drive, what file system is it using and have you made sure that there isn't some hardware bottleneck (for example, make sure you aren't using a USB-C cable that is only capable of USB 2.0 Speeds)?
We'd also like to see the log file from both computers. You can access the log file by going to Help -> Reveal Support Data. The log file may contain file paths and file names, so if you would prefer to not post that publicly, please email it to support@camerabits.com