In a situation like this you are limited in how good you can do with Defer Atmosphere because of the AA limits in the free version. So Defer Atmosphere may *not* be the best approach for this scene (hard to say though, it is probably worth experimenting a little more with).
The very first thing you should do is determine whether the rays (and noise) are coming from Atmosphere or Clouds. Try turning off your cloud layers and see whether the noise and/or rays go away. If so, then you may need to increase cloud quality rather than atmosphere samples. In fact, if that is the case, I would suggest reducing atmosphere samples way back down to say 32 (164 is reeaallly high with Defer Atmo, it will make renders take a long time), and then increase Cloud Quality to see if that helps with the noise more. Going above cloud quality of 1 is not generally needed, however if you're using Defer Atmosphere and you can't go above AA3, then it may be necessary.
Just keep in mind that with Defer Atmosphere, the quality (and noise) is directly influenced by the AA level, and since you have limits in how high you can go there, it just may not work in the end. But the most important thing is to figure out where that noise is coming from in this case...
- Oshyan
