It took me a while to move over to the new Blender version. Got my hotkeys changed and activated my favorite plugins. What I noticed is with relatively low poly objects (100k) the edit mode is incredibly slow and unresponsive compared to blender 2.79.
Just grabbing a vertex and moving it feels sluggish, selecting also. When grabbing a few (10) vertices and moving them around continuously my cpu is between 15-30% and response is quite slow. Doing the same in 2.79 it is fast and cpu sits around a comfortably 2-5%. The graphics card is idling at 20+/-Mhz and only increases in speed (2500+) when I move around in the viewport.
For the same operation Blender 2.91 uses 10 cores at 100% compared to 1 or 2 cores in Blender 2.79.
I also tried the same things without any plugins active (deleted my user profile). Turning of AA does nothing, but that is to be expected since that only increases the GPU load. I don't have any modifiers active on the model. Turning on a simple subsurf (resolution 1) in 2.91 increases my ram usages to 18GB with only 750k vertices compared to Blender 2.79 where it goes from perhaps 400MB to 600MB.
What could I change to get a more responsive Blender, as it is now I can't consider 2.91 to work with; it seems horribly broken.
My system is:
- R9 3950x stock
- AMD RX 6900 XT stock
- 32G 3600 c15 memory
- Windows 10 Pro, probably latest update as of now.
Edit 3 Also tested it on my old (and slow) laptop
- i7 6700HQ
- Nvidia 960M
- 16GB memory
- Windows 10 Pro latest updates
Edit 5 Also tested it on my new laptop (same issues obviously)
- AMD Ryzen 5900HX
- Nvidia RTX 3070
- 32GB memory
- PopOS latest updates
Small edit: the performance while not editing, like moving the view in the viewport is very fluid and not a problem.
Another edit: Things like limited dissolve are a magnitude faster in Blender 2.79. I think that the developers of Blender should first focus on getting reasonable performance (increase it by a minimum of 10 and decrease memory usage by the same amount) before it is anywhere usable. I think doing some minimal research on time complexities of algorithms might solve a lot of their problems https://en.wikipedia.org/wiki/Time_complexity#Table_of_common_time_complexities
Something tells me it has something to do with that.
I'll stick with the old Blender for now for cleaning up models before printing...
Just to note, sculpting is lightning fast; at this point I'm clueless why normal editing is so slow.
Edit 4: The issues I'm describing seem to be logged here: https://developer.blender.org/T73360 Please check that page for any updates relating to this. As a side note Blender version 3.0 is already a lot faster than 2.8+. However, it is not yet as fast as 2.79.