120Hz vs 240Hz

The 120Hz vs 240Hz question is gaining in popularity as more and more 240Hz LCD televisions become available. What is the difference? Which one is better? How does it work? And of course which one should you buy? We provide all the 120Hz vs 240Hz details below.

What is 120Hz
To fully understand the differences a quick introduction is necessary. 120Hz is common used on LCD TVs and is the speed in which new images are sent to the screen, often called frame rate because a new frame is a new image. Most TVs, refresh the screen much faster then the frame rate but will redraw the same image if a new image is not available. Since the new frame is not displayed for each refresh images that are moving quickly can appear blurry as the jump from one location to the next due to the frame rate not providing new images quickly enough to show all the motion of the moving object. The image below shows how an improved frame rate of 240Hz can display a clearer image.

120Hz 240Hz

What is 240Hz
240Hz is the new frame rate and provides additional frames, or images to be presented to the screens. The image below demonstrates how an object such as a baseball or football moves across the screen. With the squares being frames, or images, sent to the screen and the round object being the football. With the higher frame rate there are additional frames and the football is shown in more positions leading to smoother movement across the screen.

120Hz vs 240Hz

 

So What Is The Difference
To summarize, the difference between 120Hz and 240hz is 240Hz provides twice as many images than 120Hz to be drawn to the screen, therefore fast moving objects will appear less blurry and move smoother across the screen.

Which One Is Better
You may think that 240Hz is automatically better in all cases. A few things to keep in mind are that on smaller TVs the improvements will be less noticeable, the reason is that the object is not moving nearly as far in the split second between the frames being redrawn.

Think of how much further the object will need to move, over the same period of time, on a 40 inch screen vs. a 65 inch screen. The longer the distance it moves between the new frame being shown will lead to a bigger jump and a blurry image. Also, when considering 120Hz versus 240Hz, 240Hz will not provide much benefit if you are not watching programming with fast moving objects. Video games and fast moving sports are likely to demonstrate the most improvements. Of course the bigger the screen the more the benefit therefore I would not worry about the 240Hz on screens smaller than 50 inches.

Does Not Apply To Plasma TVs
You may see advertising for Plasma TVs with refresh rates at 5000Hz and think it is a typo. Actually, this likely correct, Plasma TVs work differently therefore refresh rates are not an issue with Plasma TVs. However it is unlikely the human eye will be able to detect the difference in picture quality between an LCD refreshing at 240Hz and a Plasma at the higher rate so do not assume you need Plasma to watch faster motion content.

Which Should I Buy Today
Ok, 120Hz vs 240Hz, which should you buy today? As mentioned above, for screens bigger than 50 inches, look for the 240Hz frame rate. The bigger the TV the more important this is. For smaller TVs you will not see much difference in most cases. Also look for TVs with a response time of 6ms or less. Ideally 4ms. If the TV does not respond fast enough to display the additional frames there will be little advantage to having the higher frame rate. See LCD TV selection for more on response times.

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