There are several options to measure your network bandwidth, but a simple, easy, and free solution is AJA System Test. This free utility is primarily used to measure the sequential read and write performance of your local drives, but it can also be used to measure network bandwidth with a quick tweak.
To test your network bandwidth, download the software from the AJA website, unzip it, and copy the app file to your Mac’s Applications folder. Launch the app, and you’ll see just a few simple options: the test you want to run, the drive you want to test, the file size of the test, and the type of video file that should be simulated during the test (AJA System Test was originally designed to help video professionals determine if their hardware was fast enough to keep up with intensive production and post-production tasks).
There’s just one small problem that we have to address first. In our example, we want to test the bandwidth to our NAS, which is mounted to our Mac with a volume name “Media.” But if we look in the Volume selection box in AJA System Test, “Media” is nowhere to be found.
By default, AJA System Test only lets you run the performance test on local drives. However, if we go to AJA System Test > AJA System Test Preferences in the menu bar, you’ll see a checkbox to Enable network volumes.
Once that box is checked, return to the main AJA System Test window and you’ll now see any network volumes, including our NAS volume, available to select in the menu.
To test your network bandwidth, make sure that Disk Read/Write is selected from the Test menu, choose your network drive or device from the Volume menu, set a file size of around 1 GB, and press Start.
In our example, we see sequential write speeds of 96.6 MB/s and sequential read speeds of 100.7 MB/s, which is typical for file transfers over a gigabit network. After the test, you can press the Graph and Text buttons to get specific information about the performance throughout the test.
AJA System Test won’t give you all of the information provided by some of the more advanced tools, but it’s a quick and easy way to gauge expected sequential performance and help identify network configuration issues.