My QGIS processing is pretty slow. Even using "fill sinks (wang & liu)" or "r.fill.dir" takes many hours to finish even though I use a "Intel(R) Xeon(R) Gold 6258R CPU @ 2.70GHz, 2694 Mhz, 28 Core(s), 56 Logical Processor(s)" on a high perfomance pc cluster.

Does somebody know a fix to speed it up?

With these amount of cores it should be way faster.

  • 1
    How big is your data? How many cores is QGIS actually using? It could be disk access, the cluster interconnect, or the CPU that is the bottleneck.
    – Spacedman
    Nov 26, 2021 at 11:24
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    We don't have crystal balls so you have to be a lot more elaborate about your project. What format is the data in. Where is it stored? Nov 26, 2021 at 15:29
  • Same question as before, we are missing details. Are you calling a single script or a model ? Where is the data stored ? Where are you writing the data ? Is-it a remote postgis remote ? is-it local ? What kind of format ?
    – etrimaille
    Nov 26, 2021 at 15:36
  • My data is around 5-10 gb, depends on which project i work on. There is ton of space available on my disk. Data is stored as .tif. I am storing the data on my home disk. I am running a model ( I think, I dont really know the difference :D) It only uses 1 core I think so the utilization of the cpu sits around 7-8%. While idling the cpu sits a 5-6%.
    – Tom Kurz
    Nov 27, 2021 at 9:26

1 Answer 1


QGIS is a bit of a hybrid; some functions are single-threaded (most processing algorithms) while others (i.e. rendering) are multi-threaded.

If it was a rendering issue I would suggest something else.

But I think you are working with a huge amount of data. If not, try reinstalling a stable version, it should be ok then, for 99%.

  • Rendering has nothing to do with processing. Nov 26, 2021 at 15:27

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