Without knowing your specs I would be guessing.
Use shift z to show your frame rate change the resoloution to a lower setting then recheck your frame rates. Guessing I would say that you might not notice any real differance at first. The real way to find out is to max out the weather select a complex plane such as a B747 or A320 go to a detailed airport sauch as KATL and check your frame rates again. This is probably the worst you would see your frame rates if every thing looks ok then leave it alone. Otherwise change it
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