"This software"? Do you mean LogiSphere?

If so, the answer is: "that depends".

LogiSphere itself uses very little CPU. The camera driver(s) can use a whole lot of CPU. The actual numbers vary wildly, depending on many variables including:

- What kind of camera(s)?
- How many cameras?
- What image size is selected?
- What colorspace is selected?
- What frame rate is selected?
- What operating system are you running on?
- What kind of processor do you have?

CPU usage is an ongoing topic of discussion on this issue tracker thread: http://www.logisphere.org/LogiSphereNGissues/008 I posted some sample CPU readings from one of my systems there a few weeks ago.