I just downloaded the hi res pack and changed my max texture size to 1024 to use the hi res stuff. I noticed slightly lower fps at altitude, but down low to the ground it drops from the mid 50's to around 10 fps. I adjusted the object detail and can maintain 30 fps at the middle mark and 60+ fps at "faster" mark. Its definitely worth the lower object detail to see the great aircraft textures, but I'm curious what is my limiting factor for maxing out the object detail? Is it my video card or processor? Or a number of of factors?
My info is right below and I have disabled other plane skins.