What does the graphical option "Blur" do on the PC version? Is it distance blur, motion blur or what? I understand all the options except that one. I have an x800XT PE so I'm not having any fps problems, I'd just like to know.
I don't think so. This blur is a general "softening" effect that covers everything. It's very subtle. You'll notice less "jaggies" (visible pixels on edges) with blur turned on and a slight dip in performance. Obviously not every video card may support it, but if you can, try it out and see if you like it better. You can take screenshots to compare.