The 800/1000/1100/1200Mhz setting seems to be the speed of the controller, not the hash boards.
I've not seen inside an X3, but the X1 uses a Rockchip RK3186 SoC, and these speeds match.
That's odd, because the hash speed did go down when I switched from 1000Mhz to 800Mhz.
So I'd hope there was some better way to increase efficiency of the hashing chips.
Maybe one can ssh into the machine, but I haven't tried this.