Encoding/Decoding NVR And Tour Quad Scene Questions...

Current NVR is a older model Dahua 302A16/16p4K 11-4MP and 5-8MP cams total. Once on tour 16, 8x8 display's are ok, on quad display (there are 4) where I removed 2-4MP replaced them with 8MP cameras 13-16 last quad view. It takes a second to bring up last cam other 3 populate instantly. I guess I am having latency issues with my Dahua 16ch NVR which coincides with encoding and decoding processes. Just so I'm somewhat understanding of this issue, significant processing power is required to both encode and decode the video signal. Is it true this is a Intensive task that puts a lot of load on the computer’s CPU and memory and this machine lacks processing power?

In quad view (2x2) however, is the NVR attempting to use the main stream for all four automatically and, if my cameras are set to use a 8 or 4MP+ resolution main stream, it simply doesn't have the decoding capability to display them all at once?