I have the 1600x900 screen on my new T430 with on board Intel video.
Question is, when I view a dark full size image that fills the screen on one tab of a web page then flip back to a white web site in another tab I can actually see the screen brighten slightly. Its very hard to tell but I can see it ever so slightly. The screen seems to function properly.
"The Intel® Display Power Saving Technology (DPST) is a power reduction technique that dynamically enhances the images being displayed and correspondingly modulates the backlight brightness, resulting in up to 25% savings in backlight power consumption.
"The technology, integrated in Intel’s integrated graphics chipsets, analyzes the image to be displayed, modifies the image luminance by altering the pixel values, and simultaneously adjusts the backlight brightness to adapt to the enhanced image. The image modifications and backlight adjustment occur for every frame of a video playback... various levels of aggressiveness is made available, ranging from no backlight modulation for maximum quality to the highest level of backlight modulation for maximum battery life, in order to provide flexibility to the user."