How to Troubleshoot Slow Copy Speed 4 min read

Everyone who copies digital media files will probably experience this at some point: You’ve successfully set up your equipment, started offloading the first files… and notice that the copy speed is much slower than you were expecting.

If you are in this situation, you will probably want to understand where the slow copy speed comes from and fix it. But what’s the best way to go about this?

In the following article we will provide you with a few suggestions for troubleshooting slow copy speed step-by-step.

Step by Step: How to Get an Idea of What’s Going On

Here’s an ordered list of actions that you can take to better understand your issue and where it comes from:

1. Verify Your Copy Speed Expectations

First, you should make sure that your copy speed expectations are reasonable. Your expectations are probably influenced by factors like known limits for certain connection standards, previous knowledge of the hardware, promises of the drive manufacturers, and many more. In order to understand if something is actually wrong, you first have to make sure that your expectations are realistic. Otherwise you might be chasing a ghost.

In the first place you should of course be informed about what you can theoretically expect from your specific connection (USB 2, USB3, Thunderbolt 2, Thunderbolt 3, etc.). Additionally, it is recommended that you do independent speed tests that are reliable and that make your expectations more precise and correct. Our recent blog article on how to assess copy speeds for drives might help with this.

2. Check All Hardware Components

Only if you can be sure that your expectations are realistic, and you still see insufficient speeds, go forward and make sure to check all hardware components that might possibly introduce the problem.

This is different from setup to setup but possible actions include:

  • Replace hard drive and card reader cables
  • Test and verify card reader speeds independently in other hardware combinations
  • Take additional hardware like USB hubs out of the setup

Furthermore, attaching the storage in different ways to your computer (e.g. going from a hub to a direct connection) can lead to an understanding about speed limitations introduced by additional hardware.

To give another example, limitations can also be introduced by the available bandwidth of the internal bus system of the computer. Changing the physical combination of attachment to USB ports of the computer can change the way internal busses are used and therefore influence copy speeds.

Other questions that might be helpful in this context: Did you try the rear ports on your Macbook Pro? Did you use a different combination of USB ports on your MacPro? This could help you understand more about your copy speeds.

3. Rule Out Possible Software Limitations

Only after you’ve made sure that neither your expectations are wrong, nor any hardware component introduces speed drops, you should move on to rule out certain software parts that could introduce limitations involuntarily. To get a better picture, go ahead and compare the speed results of different ways to copy files.

For example you can compare the native way of copying in your computer’s operating system with e.g. macOS Finder or Windows Explorer with speeds you see in your copy software. In the section below we list some other helpful test and monitoring tools that can help you with this endeavor.

To make your life easier concerning software testing you should generally be aware of the following:

  • If you use dedicated software products make sure you are on the latest version.
    •  Usually developers work continuously on tweaking performance for all kinds of special copy cases. If you can, try to use the latest version to benefit from all recent improvements.
  • Check operating system dependencies.
    • Also the operating system of your computer can play a role. Can you test with another OS?

Helpful Tools

There are certain tools that can help you monitor and test copy speeds:

dd Speed Test

If you are on a UNIX based system you can use the dd command-line utility to perform disk i/o tests on a basic system level. Here’s a direct link to more details on using the command for performance testing.

Activity Monitor

The activity monitor is the native way in macOS to learn more about disk read and write (input/output = i/o) operations. Go to /Applications/Utilities on your Mac in Finder, or fill in “Activity Monitor” in Spotlight. Select “Disk” on top to display disk processes.

The i/o performance in Activity Monitor

The i/o performance in Activity Monitor

iStat Menus

The iStat Menus are a well-known and easy tool for monitoring many system parameters including disk i/o.

Software products which are specialised in fast and secure copy should also always give you detailed monitoring options on the read and write operations for copy and verification jobs.

Here’s a screenshot from the copy and verification details in our macOS based application Silverstack Offload Manager:

The right bar of the Jobs panel in the Silverstack Offload Manager with job details and average copy speed

The right bar of the Jobs panel in the Silverstack Offload Manager with job details and average copy speed



About the Author
Samuel is a product manager for Pomfort's on-set applications. Usually you can catch him working on new specs for the software products, writing documentation and shooting videos for our products – and sometimes writing blog posts about workflows and equipment.