Bug report #19546

QGIS 3 slow on macOS at high resolutions

Added by Michal Jurewicz about 2 months ago. Updated 18 days ago.

Affected QGIS version:3.2.1 Regression?:No
Operating System:MacOS High Sierra 10.13.6 Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No


I use QGIS installed via MacPorts. Since QGIS 3.0.0 I noticed that it's very slow and unresponsive. Additionaly all modal windows can't be resized. However in the same time official binaries works fast but has some other problems (huge and misaligned mouse cursor and some others).

Today I made some tests with QGIS 3.2.1 and I confirmed that culprint is QT5.10. When I compiled QGIS with QT5.9 it works fast but has the same problem like official binaries. When recompile it with QT 5.10 it is very slow, size of modal windows are not adjustable but some other UI glithces are fixed.

I don't know if it is more about bugs in QT or QGIS but right now there is no option to have good user experince with QGIS 3 on MacOS.


#1 Updated by Giovanni Manghi about 2 months ago

  • Category changed from Unknown to Build/Install

#2 Updated by Michal Jurewicz about 1 month ago

Today I installed recent master with QT 5.11.1 and it's even worst. QGIS became extremly slow in every action on canvas, opening new windows and etc. Addtional mouse cursors are to big (the same problem like with QT 5.9) but modal windows are resizeable again.

#3 Updated by Michal Jurewicz about 1 month ago

I have made additional test and now I know everything. It's all about buggy high resolution support in QGIS3. It's not even about Retina multiplier but high resolution as general. General slowness is proportional to resolution. When display resolution is lower then 1600x1000 then there is no visible lag. Higher resolution are making QGIS laggy. Higher then 2560x1440 and it's more and more unsuable. Full 5K 5120x2880 is just unusable.

#4 Updated by Giovanni Manghi about 1 month ago

  • Category changed from Build/Install to OsX UI
  • Subject changed from Problems with QGIS 3 and QT 5.10 on MacOS to QGIS 3 slow on macOS at high resolutions

#5 Updated by Denis Rouzaud 19 days ago

can anyone confirm that this is really mac specific?
is anyone working on windows with resolution screen?
(will ask on the mailing list)

#6 Updated by Denis Rouzaud 19 days ago

  • Category changed from OsX UI to mac_os_specific

#7 Updated by Michal Jurewicz 19 days ago

I may try it on virtual machine but I don't know how to install QGIS on Windows with QT 5.10 or 5.11. Official installation package is with QT5.9. Is there any documentation how to do it?

#8 Updated by Giovanni Manghi 18 days ago

  • Status changed from Open to Feedback

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