My system only reports partial GPU usage, what gives?

GPU-Z screesnhot showing StarTools GPU usage
StarTools loads your GPU 100% in bursts

As of version 1.7, StarTools offloads suitable, heavy arithmetic to your system's GPU.

Depending on your GPU monitoring application, it may appear your GPU is only used partially. This is not the case; rest assured your GPU solution is used and loaded up 100% where possible.

As opposed to video rendering or gaming, GPU usage in image processing tends to happens in short, intense bursts; during most routines the CPU is still being used for a lot of things that GPUs are really bad at.

Only tasks that;

  • can be parallelised
  • are rather "dumb" in terms of logic (with few if-then-else branches)
  • perform a lot of complex calculations
  • AND process large amounts of data
  • complete in milliseconds (up to a couple of seconds or so)

...are suitable for momentary GPU acceleration. As a result, during processing, you should see processing switch back and forth between CPU and GPU.

Depending on how your monitoring application measures GPU usage, these bursts may be too short to register. Spikes are usually averaged out over time (usually 1000ms) by your monitoring application (with CPU intermittently doing its thing, leaving GPU momentarily unused). With the GPU loaded only for short times (e.g. less than 1000ms), the monitoring application makes it appear only partial usage is happening. That is, as you now hopefully understand, not the case! During any GPU usage the GPU is fully loaded up.

If your monitoring application can show maximum values (on Windows you can try GPU-Z or Afterburner, on Linux the Psensor application), you will almost immediately see the GPU being maxed out. For examples of heavy sustained GPU activity, try the Deconvolution module with a high number of iterations.


One ZIP archive contains Windows, macOS and Linux versions of StarTools. Do not download StarTools from anywhere else but We do not allow distribution of StarTools by any other party, on-line or off-line.

macOS notes

Users may have to "unquarantine" StarTools, before the OS allows it to run. Alternatively StarTools can be launched via control + clicking (right clicking) on the application, Show Package Contents, navigating to Contents/MacOS and clicking on the application.

The following command unquarantines StarTools;

xattr -dr

See the screenshots for more information, or download this detailed guide.

Download stable

StarTools 1.7.461 Maintenance Release 6 for Windows 32-bit, Windows 64-bit, Windows 64-bit/GPU, macOS/GPU 64-bit, Linux 32-bit, Linux 64-bit, Linux 64-bit/GPU (6.7MB)

Latest version released 2021-04-12 (YYYY/MM/DD)

Download bleeding edge

StarTools 1.8.518 Beta 1 Windows 64-bit, Windows 64-bit/GPU, macOS Universal Intel/ARM/GPU 64-bit, Linux 64-bit, Linux 64-bit/GPU (6.8MB)

Latest version released 2021-10-15 (YYYY/MM/DD)

Please note that beta versions may still be subject to minor changes, and may contain bugs, instabilities or other quirks. Please use at your own risk. Documentation for new modules and features is under development here.

English manual

StarTools uses AIFE.AI for content management and digital footprint. This means that the website content doubles as a printable manual and vice-versa. This content is also available as a smartphone/tablet app, virtual flipbook, virtual reality (VR) experience and more. This content will always be up-to-date with the latest information.

Unofficial English manual

Unofficial English StarTools 1.7 Manual (147MB), last updated 2021-05-09, with tips, tricks and information from various sources.

Many thanks to J. Scharmann for putting together this excellent work, as well as its German translation.

Unofficial German manual / Inoffizielle Deutsche Anleitung

Inoffizielle StarTools 1.7 Anleitung in Deutsch (147MB), letztes Update 2021-05-10.

Vielen Dank an J. Scharmann für die ausgezeichnete Übersetzung.

Unoffical Spanish manual / Manual en Espanol

Manual de StarToolsBasado en la versión 1.7 al español (7.9MB). Ultima actualizacion 2021-03-22.

Muchas gracias a C. R. Guixé por la excelente traducción.

Unoffical Spanish manual / Manual en Espanol 1.7 alpha

Manual de StarTools Basado en la versión 1.7 alpha al español (8.2MB). Ultima actualizacion 2020-10-29.

Muchas gracias a C. R. Guixé por la excelente traducción.

Technical FAQ

These are some questions that get asked frequently.

Download Android Tech Demo

StarTools 1.3.204 for Android 1.6+ Technology Demo (1.5 MB)

NOTE: Put any file you want to load in /sdcard root and name it 'file.tiff'