How to diagnose slow file transfer performance? I just bought a brand new MacBook Pro and am transferring files from a brand new external SSD hard drive. Performance is much lower than I expected.



The picture is showing ~44 MBps, which has been on par for this file transfer.



Here are the specs I'm working with and my research so far:


MacBook Pro (13-inch, 2018, Four Thunderbolt 3 Ports)
Samsung T3 Portable SSD - 1TB - USB 3.1 External SSD (MU-PT1T0B/AM)
Physically connected using the Apple Thunderbolt 3 cable that came in the box


Some research and notes:


Hard drive is not full
External drive is not full
Mac is using FileVault
External drive is using FileVault








How can I diagnose this performance issue further?
You should download the Blackmagic Disk Speed Test. It will measure your read and write speeds for your drive. You can then determine if your getting equivalent performance.  The app is free and available from the App Store. Blackmagic Speed Test is designed to determine the speed for watching a video but should serve the purpose. It will give you disk read and write speeds for your SSD.