File Writing Test

A free utility to test the write speed of your drive

This software will write data simultaneously to multiple files on your drive in order to test its write speed.

This software is designed to aid the setting up of our video surveillance software SecuritySpy, although you are free to use it for any purpose.


The current version is 1.0.1, released 25 October 2019.
System requirements: macOS 10.8 or later.

This software is free for anyone to use. Please note that this software is provided AS IS and without warranty of any kind.


Open the File Writing Test app and you will be presented with a window that allows you to choose which drive to test, and how many simultaneous files to create:

The more files you select, the more challenging the test is for the drive. If you are using this app for the purpose of testing drive performance for use with our SecuritySpy CCTV software, a useful test would be to select as many files as you have cameras.

Click the Start button, and the app will attempt to write chunks of data to the specified number of files, as fast as possible for 15 seconds. The size of the data chunks written are randomly chosen between 1 KB and 200 KB, to simulate writing various sizes of audio and video data.

Once the test is complete, the results will be displayed (the below screenshot shows results from a fast internal Solid State Drive):


  • The app may become unresponsive during the test; this is normal. Do not interrupt the test while it is in progress (e.g. do not force quit the app), as this can leave large files on your drive.
  • Before running the test, make sure to quit any other application (including SecuritySpy) that performs significant disk access, so that the results you obtain are meaningful.
  • On a fast drive, the test can take as little as 15 seconds, but on a slow drive it can take a few minutes.