Thanks Francois for the answer.
1)Yes, I need the evolution of the power by frequency during time ( I want to export the data to compute an ICA on them).
2)I did it trying to reduce the weight of the data, but I know it's not necessary since hilbert transform already apply filters;
3)These are the screens:
Do you think it may be due to the specifications of my workstation?
Thanks for the support.
Angelantonio