A pity - you got me
In fact the original tgd by FrankB was originally set to Defer Atmo OFF. I tried to compensate the blocky look by the AA 7 setting but it didn't get much smoother.
Last night I restarted both render jobs with using Defer Atmo.
Advantage:
Much better and smooth clouds especially in the distance.
Disadvantage:
Rendertimes now:
1h45min instead of 25 min on the 12-core i7 (look into the sun still incl. "Receive shadows from surfaces")
45min instead of 30 min on the 8 core i7 (sun behind us)
For increasing render speed I extremely reduced the original values for clouds quality:
aggressive acceleration and quality 0.2 (from FrankB's original settings: highest detail and quality 1.2)
With FrankB's original settings I had Rendertimes of approx. 1-2h only per bucket! I guess with these settings and using Defer Atmo I would have needed 7-8 h per frame...
Because these will be two of the last animations for the safari episode I think it's worth the effort:
The new versions:
sun in front:
[attach=1]
sun behind us:
[attach=2]