by reading through your previous posts I came up with another idea regarding your described problems.
To be honest I don’t think that the solution is based on the cabin sounds. During the beta process the Airbus was tested under some high condition scenarios to determine if there is a massive fps drop, that we eventually would need to take care off.
Therefore 3rd party add-ons (like Active Sky and REX Skyforce and ORbX) were also used on maxed out settings, which showed a significant fps drop only once completely high settings (like you wrote before) in all add-ons were used.
Could you please do me a favor and post a screenshot of your complete AS and REX setting so that we can check if it’s a texture-based issue?