I had tried 3x and 4x @ 23% as the OP suggested but there was no way I was going to be able to read those fonts - not to mention my GPU load was spiking, my FPS was jittery from 8FPS - 31FPS as an idea of the level of stuttering I was getting.

I noticed the OP said he DID NOT try anything less than 3x with an absolute 23% smoothness as the ONLY recommended number to use....I scoffed - I tried the 2x @ 33% and I am in a whole new world of FSX bliss