Setting positions of cubes directly without using transform

In a simple project with 16k cubes in it, CPU time grows up to 90milliseconds because of updating their coordinates with simple transform.position assignments.

I searched and found out that it must be done within main(UI?) thread.

Can I somehow directly write the latest coordinates of cubes without touching transform?

The lagging part is this:

     for (int i = 0; i < cubes.Length; i++)
     {
         Vector3 dv = new Vector3(x[i], y[i], z[i]);
         cubes[i].transform.position = dv; 
     }

maybe there is a way to update all array of cubes in a single step(such as swapping arrays? so I can work on detached one with multithreading?)

Also I couldn't find a way to stop UI to work on objects concurrently.(would stopping be enough?)