In Windows 7 and Windows 8, there's a setting called "Dim display after" (its powercfg ID is VIDEODIM) to control how long of an idle before the display dims (but not yet turn off).
In Windows 8.1, I can't find this setting anymore. I've noticed this in two different laptops, one with Sandy Bridge graphics and another with a NVidia 8200M G. Both laptops had the option to control the dim idle time under the advanced power settings dialog in Windows 8. But in Windows 8.1 that setting is missing. What's even more strange is that the setting to control the brightness of the screen when it's dimmed is still there--it's just the idle timeout for dimming that's missing. In both cases, I did clean installs of 8.1 RTM, and the GPU drivers in use are the very latest available.
Is anyone else seeing this? Is this a bug?