In my experience, nesting increases render times significantly, so I prerender nested segments as a Magic lossless AVI. Otherwise, lots of factors affect rendering time, motion, fades, x-fades and other transitions, ect. In general, my MP4 files render at about half of real time or so with the Magix or MainConcept AVC codecs. VP-16, Win 10, 32 GB RAM. I also usually render the audio separately and mux it in.