Can it just be like a consumer grade CPU i.e. an i5 or an i7 or would we need a xeon server to capture and render CCTV camera footage (This is a theoretical question)
We've got 35 IP camera's feeding into a Xeon E3 server with 8GB ram. Resolution ranges from 480 to 1080 all doing 20fps. What I've learned is that the faster your storage system, the better. Don't do any RAID except RAID 0, use the fastest hard drives you can.