That computer would be fine. Other than needing an 8th gen or newer for Win11, a 4th gen can run 50 cameras...
The difference between the Z12E and Z4E (other than the Z12E is 2MP and the Z4E is 4MP) is the focal length.
As I pointed out in the thread I linked, focal length for the distance you want to IDENTIFY is more important than MP.
If you want to IDENTIFY up to 60ish feet, the Z4E is the proper choice. If you want 100 feet, you need the focal length of the Z12E as an optical zoom image of a lower MP will almost always beat a digital zoom of a higher MP camera, especially at double the distance.