May be that's the volumetric clouds because my weather setup was in thunderstorm and 4km vis, ceiling 2000 ft. I use ActiveSky Beta.
I can only tell there is significant difference on fps between EA on / off for the same setting. May be that's just my settings.
Just a side note, I have no fps problem with the same settings (same weather, same scenery) on the PMDG, so I guess my computer is OK to handle the load.
As many did after SU5+Hotfix I noticed a considrable reduction in graphics quality. I have always been able to have all settings att Ultra, with beautiful results.
However, someone at the MSFS forum wrote that after SU5, what appeared to be unchanged graphic settings in the Options menu in MSFS, might infact not be the case.
So I started a flight at ESSA Arlanda. Looked not very good. Opened graphic settings, still on Ultra, changed to Medium, saved and applied and then again back to Ultra, saved and applied.
Resumed flight - and what a different!!! Suddenly back to a detailed airport and beautiful skies. Now I cant say if it is better or worse than before SU5, and I have only tested at Arlanda so far, but it is evident that this might be a quick fix to get the graphic quality up again. And I have made a bug report to Zendesk.