That doesn’t make sense, we are not using a single plotter! We always use plotters in parallel.
The absolute fastest I’ve seen a plot finish myself, on hardware I own, is 270 minutes (4.5 hours), that is 5.3 plots per day. With that machine we’d need 9 parallel processes, and no speed degradation as we increase the number of plotters… fat chance of that! So it’s a question of
- how many plotters
- when do the plotters start
- how fast do the plotters finish once fully loaded
The general rule of thumb I use is to stagger so you are starting a new plot as soon as phase 1 completes; that is 44% of the total plot time.
I read that 8 threads is actually worse than 4, so I am puzzled by a lot of this @harris… perhaps there’s some magic in the 8 threads when everything is under full load? I always do 4 threaded plots, except on my 4c/8t machines where I do 2.
I’ve hit 51 (now 52 after the queue levelled out) plots a day (12 parallel) on my Linux 5950X machine (not overclocked)
So 12 parallel to hit 50… means each of those 12 must be doing 4.16 plots per day, or 346 minutes per plot, under 21000 seconds per plot or 5h46m? 
On another Ryzen 5950x I just set up, I see 21000 seconds or under for the very first plot (low contention from other plotters), but 25000, 26000 seconds for the subsequent plots. To achieve 50 per day, at 12 plotters, all of the plotters must be doing 21000 seconds or better.