Is it just me? (Subdivision surface modifier extremely slow when adding geometry.)

Hi people!
It’s been a while since I used subdivision surface modeling.

I’ve just found out that, when editing an object with subdivision surface modifier on, if I add new geometry (extrude, add edge loop, etc) the viewport freezes for about 4 seconds before it lets me move the newly added geometry.

This is happening with Blender 2.90.1 and I’ve tried 2.83.7 with the same results.
When I try the same with Blender 2.79 it behaves normally!

Take a look:
(the time in which the cursor is not visible is the time Blender is taking to add a new loop)

Any clues why this is happening?
Is it just me?
Any setting I’m not aware of?
Is it a bug?

I’m aware that in 2.79 there’s an option (settings -> system) to choose OpenSubdic Compute. I can’t find such setting in 2.90.
My hardware is recent.

Thank you all in advance for your time!

I think it happens mostly when your mesh contains polygons with many vertices. Try poking the top and bottom faces of the cylinder and see if it improves the performance.

For whatever reason, the 2.8x+ series still does not have accelerated subdiv and the best you can get is a few frames per second with one object with a subdiv level of 1. I still don’t know why fixing this is not more of a priority, when 2.79 even just with the multi-threaded CPU-only acceleration can hit 60fps on a complex subdivided object. I see animators complaining bitterly about this on a regular basis.

2.8x does have a geometry cache that prevents needing to completely re-evaluate the opensubdiv stuff as long as the topology does not change and that can double the playback performance (though twice nothing is still nothing) however it also means that when modeling every time you change the topology it has to recompute it all from scratch so you get the worst possible performance.

If possible, model with the subdiv modifier disabled.

Hi ejay. Thank you for the input. That would make some sense if I was working with some heavy geometry. But it’s only a cylinder! …and as you can see 2.79 behaves smoothly. I think Zoot knows what he’s talking about.

Thank you for this Zoot! I don’t remember Blender’s subdiv performance being so bad as now. Even years ago when I used a shitty core duo macbook to do my stuff. Fortunately I don’t use subdiv as much as before. But when I do… what a nightmare!!
I think I will report this as a bug.