when using AEFS2 with unrestricted FPS.
If I set FPS limit to VSync ( I don't use this one because it causes lot's of stuttering ), 120 or 240, everything is fine, but if I set the FPS to no limit, my PC starts making a strange high pitch noise, as if it was music, changing when I change views or menus... It is really weird, and apparently goes OFF when I START the flight ( or the sound of the aircraft overrides it ? ) ...
It's not the graphics board fans.