I want to have a program running in the background that performs a lot of calculations. The problem is, this program takes up 99% of my CPU and makes all other programs run very slowly.

I want to be able to have this program performing its calculations in the background and still be able to use other programs meanwhile, without the calculating program significantly affecting the other programs' performance. I don't mind if this means that the calculating program will run slower.

Is there a way I can do this?