I made a test with 25M faces dummy mesh,
by default it takes 10.94 GB in ram, which is already way too much.
When going in edit mode, it takes 48 GB, so basically like 2KB per face
I thought I was way too huge, so I tried again with a smaller mesh to see if that was not a memory leak issue
More or less exactly the same result.
I don’t know how is stored data inside the blender engine, but 2KB per face is wrong.
Is it a know issue, or a optimization not yet implemented, or something that needs to be changed ?