Difference between Mujoco and Isaac Gym

Hey, I am working on a reinforcement learning project where we want to train robot manipulators for different tasks and want to do this in parallel.

I am just wondering at the moment what’s the difference between Mujoco and Isaac Gym is in terms of precision’s of the internal calculations and overall.

Would it be possible to combine both ?

All best and thank you very much for your help. I would highly appreciate any sources and information on this.