Follow these directions to test your drive's read/write speeds.
If testing an external drive, connect that drive to your computer
Launch Blackmagic Disk Speed Test
In this window, click on the Gear Icon
In the drop down menu, choose Select Target Drive....
In this window, navigate to a folder on your external drive and select it. Then click Open
Now click the Start button and let a full test complete (both write and read)
Note: You will need to manually stop the test once both have ran
Now take a screenshot of the results by hitting command-s and save that screenshot to your desktop
Send screenshot to requestor via email