Hardware requirements are always interesting, but tricky questions. First I assume that the computer will only run NCS. Unfortunately, we have no rule or anything since it differs a lot from case to case. However, here are some guide lines that makes a difference:
- 64 bit OS and 64 bit NCS.
- NCS is not heavy on RAM so 8 GB is enough.
- if you have many MP cams in motion detection or continuous recording a quad core processor is valuable.
- a processor with hyper threading makes a big difference since video transcoding using ffmpeg is highly threaded. there are many discussion on the net about number or cores, threads and processor speed.
- SSD or regular HD is not crucial in moderate applications for internal drives. For external drives the interface is more important, but I have no actual numbers. In one system I am using a NAS as external storage on a Gbit LAN with no problem.
- since budget is important (which it usually is) I would put the money on the processor instead of SSD. Most likely it will be interesting to add cameras to the system in the future.
- multi core and hyper threading processors are more expensive and is usually an i7 processor (if not in a server).
- FPS affects the CPU load a lot.
For the moment we are evaluating hard ware acceleration for more high end security applications using DXVA2 or QuickSync. DXVA2 has not given the results we were hoping for compared to development efforts ;). DXVA2 is in the pipe line.
If you have said 8 cams I would have recommended and i7 quad core with hyperthreading. With 4 cams an i5 quad core or standard i5 can also be very fine. I assume you have one or two computers around so you need to do some testing. A standard i5 dual core processor is today very competent.
Sorry, for not giving the perfect answer, but it is not that straight forward. If you start with one cam and look at the CPU load of the NCS server it scales rather well when adding more cams.