Hello @Top999gun .
As far as I am aware, voulumetric effects are always resource intensive. I am not sure if it can be optimized further, but considering e.g. how the clouds look and how many there can be, I am quite impressed the FPS hit isn’t much larger.
My guess would be that completely removing tress, buildings or flight instruments would show a similar or even heavier “fps increase”, so I am not sure if turning off volumetrics and then checking fps increase is a very useful metric here.
According to the following guide decreasing the cloud setting can bring about 8fps, but reducing other settings like terrain level of detail can cost you even 20fps…
For me 10fps difference for clouds in a flight simulator is worth it and I would not consider it to be a bug with the currently available information.