Indeed. It's the frequency of pixel changes causing ripples in voltage rails, subsequently causing inductors in switching voltage regulators to physically reso

Indeed. It's the frequency of pixel changes causing ripples in voltage rails, subsequently causing inductors in switching voltage regulators to physically resonate at audible frequencies. There's specific test images you can find online, designed to maximally stress voltage rails in LCDs. Lower end monitors can actually get enough voltage ripple that the image quality visibly degrades.