I am using QGIS 3.24.2 Tisler. Machine is an i9-7900 @3.30 Ghz 64 GB RAM using Windows 11 64bit. Disk is SSD and Gfx card is a RTX2060he

When doing a raster merge (Raster - misc - merge) of multiple asc files QGIS is only using a single logical core. I can see that core being maxed out with all the other 19 sitting there idle. Disk I/O is minimal and GFX card utilisation is again minimal. Memory utilisation is about 15%

In options I have Render layers in parallel using many CPU cores enabled.

Is the merge a single core operation or should it be using multiple cores? If the latter any idea whay it isn't doing so?

  • Raster rendering has nothing to do with GDAL libraries. docs.qgis.org/testing/en/docs/user_manual/processing_algs/gdal/… May 5, 2022 at 11:30
  • So does that mean that waht i am attempting to do is a single core activity or is it possible to have it use multiple cores? If it is how? May 9, 2022 at 10:27
  • This means that you need to find out if the GDAL library supports multiple processors for data processing. May 9, 2022 at 11:24
  • I am not being deliberately obtuse here but i have no idea what you are talking about. the link you provided is no help at all without some context. does the operation i am doing have multi core support, or is it a singe core operation? if it depends on a setting or a particular configuiration what is that setting? May 9, 2022 at 21:30

1 Answer 1


One of the GDAL tools (gdalwarp) supports multiprocessing: Does GDAL support parallel processing?.

To use it as described here, you must use the -multi keyword.

It seems merge tool does not support multiprocessing because there is no such option in the merge tool description.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.