In regards to Blueiris, I wanted to run with as little power as possible and managed to get my blueiris setup with 12 HD cameras constantly recording to NAS on an little i3 intel NUC with just 8gb ram. This runs with a very low cpu footprint of only 20-30%, I managed to get such a low footprint by setting the “record directly to disk” option. This means that the server does not re-process any of the frames and saves the stream into the container you choose. Upsides is low cpu overhead and maximises original quality without second transcode of material. Downside is you cannot record any overlays from blueiris onto the recordings, eg. timestamps or motion highlighting boxes.