Copio el comentario de un usuario de rtings.com sobre el tema de los Hz. Las negritas son mías.

Fake Refresh Rates Conversion: Samsung Clear Motion Rate vs Sony MotionFlow vs LG Motion Clarity Index


For clarification, the refresh rates listed, even if they are only of the 120/240 Hz variety are still misleading. Here's why.
First off, there is no "LED" panel. All panels are LCD. LCD/LED refers to backlight only. All consumer LCD TVs have a fixed maximum refresh rate of 50/60 Hz depending on whether or not they are PAL or NTSC systems respectively. The 120/240 Hz specification is not the *panel* refresh rate, but instead the CPU's frame processing rate. That is, a 120 Hz TV can process 120 frames internally and a 240 Hz TV can process 240 frames internally. This internal refresh rate (I hate using that term for CPU processing) is of use only for frame interpolation on modern sets.
Frame interpolation is where elements of at least two successive frames are received and analyzed by the TV's CPU for processing. On a 120 Hz TV, the frame interpolation will work fairly well for 24 FPS and 30 FPS material as both fit into 120 at least three times. For 60 FPS material such as console games, computer display signals from a GPU, and certain broadcast signals, the frame interpolation used for motion blur reduction suffers from "hiccups". It is often referred to as the "hurry up and wait" effect where the motion smoothing will appear OK for a few frames, then suddenly de-sync for a couple of frames, and repeat the cycle. This is because there is no time to process the two key frames needed to go along with the third interpolated frame. At 60 FPS, on a 120 Hz TV, the TV can process two frames per refresh cycle, which does not leave enough time to inject an interpolated frame every other frame, which is necessary for motion smoothing to work properly. That is why TVs need processing at least three times the panel's refresh rate so that it can inject the interpolated frame in the time of each frame cycle.
In order to avoid the de-sync issue, a TV would have to have internal processing of at least 180 Hz for 60 FPS material to be displayed smoothly. However, there are only 120 Hz and 240 Hz TVs on the market (I ignore all those specifying higher Hz ratings because past 240 Hz there are no gains for frame interpolation). While a 120 Hz TV can perform proper motion smoothing on 24/30 FPS material with virtually no de-sync problems, a 240 Hz TV is needed to perform motion smoothing without de-syncing. In the case of a 240 Hz TV, the CPU in the TV has time to create three key frames and one interpolated frame from that data each cycle. In fact, true 240 FPS (Hz) internal processing leaves headroom in case of any signal issues or errata in a frame. This is why the soap opera effect is so much more pronounce on a 240 Hz TVs than 120 Hz TVs - with more time to process the key frames and interpolate a frame internally and headroom on top of that, the effect is much smoother and more consistent.
As for computer use, the reason the TVs won't accept a 120 Hz signal is because the panels are 60 Hz maximum. The only possibility of that changing is if the TV is 3D capable and accepts dual field 60 Hz stereoscopic 3D signals from the GPU or if the panel is upgraded to be a true 120 Hz (8.335ms) response time display.
Samsung is unfortunately leading the market once again with its disengeuous specifications on its 4k UHD TVs. Those TVs can process 1080p at 120 Hz/FPS, but can only process 4K (3840x2160) at 60 Hz/FPS. Despite Samsung's claims of HDMI 2.0 compliant ports, their H6950 TVs do not use true 4:4:4 chroma signaling. Instead they use 4:2:0 chroma subsampling, a method that is not an official HDMI 2.0 spec, but was added in HDMI 2.0 as an "unsupported" spec. This is to allow the TV to receive 3840x2160p60 signals over HDMI 1.4 systems. It is no coincidence that nVidia used the same trick with their Kepler GPU drivers, which also send only 4:2:0 chroma signals to the TV/monitor instead of 4:4:4 chroma signals. This is to reduce the bandwidth needed so an HDMI 2.0 compliant port is not required. Sadly, even the GTX 980 from nVidia can still only net you a 4:2:0 signal into Samsung's H6950 TVs even though those cards have true HDMI 2.0 ports capable of 4:4:4 chroma signaling @ 60 Hz. This is why nearly every review of the Samsung H6950 series is negative when coming from somebody using it as a computer display. It can display 1080p at 4:4:4 chroma, but not 2160p. Such is the misleading way of Samsung. At the time of this post only Panasonic has a true 2160p60 input that can handle 4:4:4 chroma signals because it is the only one with a DisplayPort 1.2 port. If you are intending to get a 4K TV to use as a computer monitor, be aware that you will most likely need to wait until they start putting DisplayPort 1.2 connections onto their sets as that is the only way to guarantee a proper connection and color reproduction.
Anyway, bottom line is this: If you need motion smoothing for only 24 FPS (Blu-Ray) and 30 FPS (DVD/OTA Broadcast), or 60 FPS Interlaced (DTV) material, a 120 Hz TV will suffice. If you intend to use 60 FPS (progressive scan) material with motion smoothing, you will need a 240 Hz TV to avoid de-sync issues. For PAL regions, substitute 100 Hz/200 Hz TVs for the 120 Hz and 240 Hz specified for NTSC respectively.