This is true. AI traffic draws a lot of CPU power. Although, I didn’t mention this above, but I also have multiplayer and AI Live Traffic on.
Clouds have never seemed to bother me or change that much (maybe lose 3-5 FPS… so from 45 to 40). I fly mostly GA (which in and of itself is different than the A320), but with the G1000 if I turn off the synthetic screen I get 5 more FPS, so if I’m flying, I turn that off and get back the frames that were lost with the weather.