Performance drop in sculpt mode on same mesh

There are two identical meshes.
The only difference is in units. 1 - in mm, 2 - in cm.

I changed the size of the mesh in the slow file and it still remained slow.

1 - sculpts quickly, 2 - sculpts slowly.

Two windows of the same blender version are open. 1 - file is fast, 2 - file is slow.

I think there are a lot of things that need polished and recoded for the geometry engine.
(Like the gigantic level of memory used for storing data in ram too)

Units that affect perfs sound like the higher scale call for more precision in the point values, instead of packing a constant precision in variable matrix.

As a solution, I tried to export in the gltf format from 2.7 to 2.8
It helped me.

It is strange that when I loaded the obj mesh from 2.7 to the normal mesh, the normal one also became slow