How can I simulate a bunch of robots in real-time?

Hi, I try to simulate a bunch of robots.
I run 8. Multiple Tasks — Omniverse Robotics documentation and set self._num_of_tasks to 30.
The simulation becomes very slow, especially the manipulators pick up the cubes.

How can I simulate this kind of scenario in real-time?
Does Isaac Sim use GPU for physics simulation by default?