Even though Archicad 19 is faster than ever, performance related issues can come from various causes. Most of these issues can be due to the insufficient Software/Hardware availability or the way how the project is created in Archicad. Depending on the nature of the issue you experience check the categories below. For generic issues, please see this article
Selection and Navigation in 3D becomes slow and can even freeze in case textures with huge resolution are displayed in Archicad 19 Update 6006
If textures with 4096 pixels or more in either dimension are displayed, navigation and selection in 3D becomes slow and can freeze in Archicad 19 Update 6006. The issue can appear with textures bigger than 2048 pixels if the texture tiling is set for either of the 3 mirroring options (see below)
Texture handling process has been changed in Update 6006.
Use textures with lower resolution than 4096x4096 or change the tiling to the non mirroring option if 2048 pixel or bigger textures are used. Or install the latest Archicad 19 Update 7006.
Opening Section/Elevation gets slow or seems to freeze
If the Report Window gets opened from time to time (e.g. because of missing GDL macros), it is possible that you will experience freeze or slowdown at opening Section/Elevation views.
The Report Window opening process slows Archicad down a little bit. The more content the Report Window has and the more frequent it comes up, the slower Archicad will be.
To workaround this situation we advise to delete the content of the Report Window regularly or to eliminate the problems that are reported there (e.g. to replace the missing GDL macros).
NOTE:This problem will be fixed in a future version of Archicad.
2D pan and zoom gets slow and laggy when a 3D cut plane is active
If you place a 3D cut plane in the model, pan and zoom gets slow and laggy in 2D views.
3D cut planes are projected on 2D views for better navigation. Thus, when a 3D cut plane is active, Archicad will try to refresh the 2D projection constantly, as you move around in the 2D view. As a result, if you have a big or complex model, this refresh may cause a lag in navigation.
Turn the 3D cut plane off, while you're in a 2D View.