Bug report #19546
QGIS 3 slow on macOS at high resolutions
|Affected QGIS version:||3.4.2||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.
#2 Updated by Michal Jurewicz 5 months 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 5 months 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.
#11 Updated by William Kyngesburye 3 months ago
Here is an installer for QGIS 3.2.3 built with Qt 5.11.1.
#13 Updated by Michal Jurewicz about 1 month ago
Just for your information, QGIS 3.4.2 (QT 5.11.2) is still very unresponsive. Below some screen records with small project. Just panning and zooming the map and closing the project. As you can see it's very slow. I use iMac Pro - it's Retina 5K resolution.
I hope that QT 5.12 is going to fix it.