Bought the week of its arrival in stores and works out of the box. CPU clock modulation works perfectly. When idle, it kindly steps down to 1.2 GHz.
I'd like to reduce the idle power consumption of my computer, with the goal of keeping it always on without a large impact on my energy bill (energy is quite expensive over here.)
Using HWMonitor I can see my CPU (Intel Core i5 4690k) throttles itself down to 800 MHz when idle, my GPU (GTX970) to 135 MHz core clock and ~270 MHz memory clock.
Intel now sell their CPUs with an advertised Core Clock speed, and a Turbo Boost (up to) speed.
As well as this, thanks to SpeedStep (dynamic frequency scaling), a CPU will often underclock to conserve power and reduce heat.