I'm looking at upgrading my NVR. I currently have the DS-7608NI-I2-8P running 6 Colorvu cameras on quite low settings as the NVR can't handle the bandwidth on full settings. I've been looking at the DS-7616NI-M2/16P or the DS-7716NI-M4/16P. They both have 256Mbps bandwidth. Is there any benefit of one or the other, or any other options.