REFRESH RATES IN SMARTPHONE DISPLAYS

Refresh rates in smartphone displays is the new big buzz in the smartphone world at the moment. You can find it on almost every advert nowadays. Companies are trying very hard to outdo each other in this new refresh rate arms race. With all this fuss and buzz, the question you may be asking is…


What are Refresh Rates?

Refresh rates in Smartphone displays is the frequency (number of times) at which a display is updated or refreshed. It is in other words, the number of times that your display redraws the image on your screen.

As you are using your phone and switching between applications, looking at photos, watching a movie or scrolling through the internet, the information on your screen changes. In order for this to happen, the pixels on your screen have to be updated constantly to show (or redraw) the latest information that you are supposed to viewing.

The number of times that a display updates itself to display the new (or current) information is its refresh rate. Refresh rates are measured in Hertz (Hz).


Read: Smartphone displays explained


Refresh Rates

Refresh rates are measured in milliseconds or in Hertz (Hz). Hertz is more commonly used it is more impressive and better for advertising.

There are 4 main refresh rates used on smartphones today. These are:

  • 60Hz
  • 90Hz
  • 120Hz
  • 144Hz

The standard refresh rates in smartphones (and other displays) is 60Hz. This means that the display is updated sixty (60) times in one second or once every 16.67 milliseconds (ms).

The next step up is 90Hz. A screen with a 90Hz refresh rate updates or refreshes itself 90 times per second or once every 11.11ms.

A 120Hz refresh rate is found on the displays of flagship smartphones as well as other high end electronics. A 120Hz display refreshes its pixels 120 times in a second or once in every 8.33ms.

The 144Hz is also another really fast refresh rate that can be found on phones. A 144Hz display refreshes 144 times in a second or once in 6.94ms.

Outliers include 160Hz and 240Hz.

The formula for converting refresh rate in Hertz (Hz) to milliseconds (ms) is

Milliseconds (ms) = 1000/Refresh Rate (Hz).


A brief history

Up until recently, most smartphone makers were content to leave the refresh rates of their products at the standard 60Hz refresh rate. Then the One Plus 7 Pro was released in 2019 with adverts focusing on its refresh rate, which many other smartphones did not have. This move by One Plus brought refresh rates to the awareness of the general public.
Now while One Plus could be credited with starting the refresh rate craze, they were not the first company to use a refresh rate over 60Hz in a smartphone display. That title belongs to Sharp who used a 120Hz refresh rate display on the Sharp Aquos Zeta SH-01H which was launched back in 2015.

The first 144Hz display can be found on the Nubia Red Magic 5G which was released in March of 2020. It was the phone with the fastest display in the world until Sharp returned and threw the kitchen sink at them, releasing the Sharp Aquos Zero 2 with a 240Hz refresh display in May of 2020.
Honourable mentions include the Razer phone which popularized 120Hz refresh rates.


Benefits of high Refresh Rates

On screens with high refresh rates, animations and motion graphics are smoother and noticeably faster. This leads to a much better experience whilst watching movies, browsing the web or simply scrolling through your phone. It also reduces or almost totally eliminates screen lag or latency.

High refresh rates is also very good for gaming as graphics would display smoother and faster. This is very crucial in First or third person shooter games that require split second decision making. That half second advantage afforded by using a faster display could mean the world in a game like PUBG or Call of Duty Mobile.

[Slow motion] 240Hz vs 144Hz vs 120Hz vs 60Hz - Monitor refresh rates


Disadvantages of high refresh rates

Higher refresh rates over 60Hz and sometimes 90Hz put an increased strain on the SoC and increases battery consumption. Displays with extreme refresh rates often suffer from washed-out colors and flickering. There is also huge risk that (depending on the type), the display could suffer burn ins especially if it is an AMOLED.

In some cases, the entire display could even die early because it is refreshing so fast. Basically, a 240hz monitor can be a waste of money. They are also much more expensive.


Read Smartphone Display Brightness (NITs)


Trends

Refresh rates in Smartphone displays is new big thing now. Most 2020 flagships have really high refresh rates and that is expected to continue in 2021. 120Hz seems to be the standard for most flagships but it is also the same for upper midrangers now. 90Hz is starting to trickle down to the lower midrangers.

Many OEMs have also tried to mitigate the battery consumption and heating by allowing users to switch between different refresh rates on their devices especially on none LTPO displays.

Another option is also Adaptive/Dynamic sync that adjusts the displays refresh rate according to activity that the display is carrying out. If you are watching a movie, it could go down to 60Hz and then jump up to 90Hz or even 120Hz if a game is being played.

Some companies also allow the refresh rates on their devices to be overclocked beyond the maximum refresh rate. A good example is the Asus ROG 3 which can be overclocked from 144Hz to 160Hz.


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