Independent of hard drive or wifi on/off, Lenovo BIOS saves about 1.5W. It could be due to the screen backlight, it is a TN screen, so there may be some difference from the IPS. I didn’t recompile coreboot myself, but looking through the skulls settings, it isn’t clear if there are additional power savings that could be had from there.

Assuming that this is a large enough data set with the X230, it definitely consumes less power than the X200. On power hungry tasks, such as browsing, the X200 would regularly consume 15-20 W while the X230 rarely goes over 14W.