overly long simulation

Hi!

I'm running a simulation with a simple model of a room of about 303 cu. m. (5,6x4,3x12,6), so not very big, but it takes almost 20h per source to complete.

At the beginning I thought it was due to the low-performances of my laptop, but trying on a powerful workstation didn't significantly change the running time. So is it normal or am I doing something wrong?

I'm attaching the model and the simulation data.
Thank you in advance for your help!

Valentina