If you're in the market for a new TV, you've probably come across a spec called "refresh rate" while browsing the best deals. What's that all about?
Thanks to the way marketing teams play with numbers, you've probably seen listed refresh rates from 60 to 480 Hz. But really, there's only two real ones right now: 60 Hz and 120 Hz. And while that helps simplify things, you may still find yourself forced to pick between the two.
Fortunately, while some of what differentiates 60 Hz and 120 Hz TVs is complicated to engineer, it isn't complicated to understand. All you really need to know is what kind of content you want to watch on your new TV.
What's the difference?
Fortunately, the difference between 60 Hz and 120 Hz is pretty simple. In the case of television refresh rates, "Hz" just means "refresh cycles per second." So a refresh rate of 60 Hz means the screen re-samples or re-displays source information 60 times per second. And with 120 Hz, it's twice as often. Pretty simple, right?
Just keep in mind that regardless of the TV's refresh rate, it can't create more information than the source is displaying. This is a key detail in determining whether or not you need a 120 Hz TV, or can settle for a 60 Hz option.
Is a 120 Hz TV always better?
Short answer? Yes, but that doesn't mean it's always necessary.
If you just want the most high tech TV money can buy, a 120 Hz option is never going to do a worse job than a 60 Hz option. Sure, it isn't twice as good just because it's twice as fast, but logically it won't ever miss any source information that a 60 Hz variant wouldn't. However, the real draw of 120 Hz TVs is that they can play 24fps film without judder.
In the early 20th century, cinema experts decided that 24 frames per second—also called 24fps or 24p—was the minimum necessary amount of frames to convince human beings that they were seeing moving pictures. Far from outdated, many of today's Blu-ray discs still default to 24 frames per second to preserve the filmic aesthetic you'll get at the movies.
The average 60 Hz LCD TV can't render native 24 fps content without a little bit of help, since every three seconds the TV gets out of sync. To combat this, many modern 60 Hz TVs use a telecine technique called "3:2 pulldown," where frames are doubled in alternating sequences in order to "meet up" with the locked 60 Hz display speed. Unfortunately, 3:2 pulldown usually results in a motion artifact called "judder," where in-motion sequences during playback have a stuttering or skipping effect.
While many modern 60 Hz TVs do 3:2 pulldown so successfully that you'll never notice the tiny amount of judder, you can save yourself the trouble by purchasing a 120 Hz TV instead. Since 120 refreshes per second can allocate a smooth 5:5 ratio for 24fps content, 120 Hz TVs can handle native 24fps content without judder.
Do I need a 120 Hz TV?
Complicated mathematics aside, whether you need a 120 Hz TV or not really comes down to content. You might think, "I definitely want to be able to watch native 24p content! No way am I getting a 60 Hz TV," but it's less of a discrepancy than it seems at first glance. While you'll want a 120 Hz TV to enjoy "filmic" Blu-ray content with the least amount of fuss, most other kinds of content work with either.
- Do I need a 120 Hz TV for cable/satellite broadcasts of TV and movies?
Broadcast television in the U.S. plays at either 30 or 60p, fitting into a 60 Hz TV's refresh timing and therefore not introducing the same judder effects from 3:2 pull down.
- Do I need a 120 Hz TV for Netflix, Hulu, or other streaming services?
Other than a few exceptions, getting 24p playback from streaming providers like Netflix isn't possible. Almost every streaming service adjusts resolution and buffering to play smoothly at 60p, making a 60 Hz TV perfectly capable of good playback.
- Do I need a 120 Hz TV for console or PC gaming?
If you enjoy console gaming at home, you'll be glad to know a 60 Hz TV is, again, just fine. Even the newest consoles—namely the PS4 and Xbox One—only support up to 60fps right now, and likely will going forward.
Where this differs is in PC gaming. Especially with competitive PC gaming, titles often excurse well above 60fps, and many modern gaming monitors will offer 120 Hz or even 144 Hz refresh rates in order to capture the best gaming experience. While a 120 Hz TV isn't necessarily the perfect display to pair with a PC game, it's going to handle things much better than a 60 Hz option.
How do I know if a TV is 60 Hz or 120 Hz?
I wish I could say it was as simple as checking a spec sheet, but refresh rates are often represented in a confusing manner. For at least the last decade, TV manufacturers have implemented so-called "motion interpolation," sometimes called motion smoothing, motion assistance, or the "soap opera effect."
Keep in mind that this kind of interpolation, while available in some form on almost every TV, doesn't have anything to do with whether the TV is a 60 Hz or a 120 Hz model. Such modes—which Samsung calls Auto Motion Plus, LG calls TruMotion, and Sony calls Motionflow, for example—are a type of motion aiding software, and can be implemented in either a 60 Hz or a 120 Hz television set. And while some types of content can certainly benefit from these modes, they aren't the same thing as a hardware-level refresh rate.
However, there are ways to find out a TV's true refresh rate. Spec sheets on sites like Amazon and Best Buy often list real refresh rates, and often times manufacturers' product pages are reliable too. But if a manufacturer lists an "effective" refresh rate, the TV's actual native refresh rate is usually half of the advertised effective rate, and other factors—like smoothing and backlight scanning—are sometimes used to multiply refresh rates into higher and higher numbers, such as "480 Hz."
Ultimately, your best bet is to check out unbiased sources like enthusiast forums and professional reviews—here's a good place to start.