4K monitors can generally be compatible with older devices, but there are several factors to consider. Compatibility largely depends on the output capabilities of the older device, specifically the graphics card and the available connection ports. Many older devices might only have HDMI 1.4 ports, which can technically support 4K resolution, but only at a 30Hz refresh rate, leading to less smooth motion on screen. Newer standards, like HDMI 2.0 and DisplayPort 1.