Global Texture Resolution Question

I have recently noticed that with a new scenery I bought that for me to run it with the same performance as the default scenery that I must turn my GLOBAL TEXTURE RESOLUTION down to HIGH from MAX. If I leave it on MAX I get huge FPS swings at different views ranging from 30 at times and drops to 4 all of the sudden. If I set it to HIGH problem solved. This only happens with the new scenery. Im OK with the HIGH setting but MAX looks far better in the VC. Any one else see issues like this?