The question of whether 120 Hz is the same as 120 fps is one of the most persistent misunderstandings in display technology and gaming. While the numbers sound identical, they refer to two completely different concepts that work together to create a smooth visual experience. Confusing these terms leads to unrealistic expectations when upgrading monitors, TVs, or graphics cards, and it is the primary reason why a 120 Hz screen does not magically make a 30 fps game look like a 120 fps game.
Understanding Hertz (Hz) and Frames Per Second (fps)
To clear up the confusion, it is essential to define the distinct roles of Hz and fps. Hertz (Hz) is a unit of frequency that measures how many times a display refreshes its image every second. A 120 Hz monitor physically updates the picture 120 times per second, regardless of what content is being shown. Conversely, frames per second (fps) measures the performance of the source device, specifically how many individual images the graphics card or camera can produce in one second. The display is the window, while the graphics card is the content being fed through it; one cannot create information the other does not have.
The Relationship Between Refresh Rate and Frame Rate
The relationship between refresh rate and frame rate is analogous to a pipe and a pump. The refresh rate (Hz) is the size and capacity of the pipe, determining the maximum flow of information it can handle. The frame rate (fps) is the pump, determining how much data is being generated to push through that pipe. If you have a 120 Hz television (the wide pipe) but your game is only generating 60 fps (the pump output), the television can only display 60 of its 120 refresh cycles with actual new data. The remaining cycles either display the same frame twice or result in screen tearing if the synchronization is off.
Screen Tearing and Input Lag
When the refresh rate and frame rate are mismatched, visual artifacts occur. Screen tearing happens when the display shows parts of two different frames in a single screen draw, creating a fractured or smeared appearance horizontally across the image. This occurs because the monitor finishes drawing one frame and starts drawing the next while the graphics card is still sending the next complete frame. To mitigate this, technologies like V-Sync attempt to lock the frame rate to the refresh rate, but this often introduces input lag, where actions on the controller or keyboard feel delayed because the system is waiting for the perfect moment to send the frame.
The Practical Benefits of a 120 Hz Display
While a 120 Hz monitor cannot display 120 fps if the game is only running at 60 fps, a high refresh rate provides significant advantages when the hardware can keep up. If you have a powerful PC or console that consistently outputs 120 fps, a 120 Hz display is necessary to capture that smoothness. The primary benefits of the higher refresh rate are reduced motion blur and improved responsiveness. Fast-moving objects appear sharper, and the transition between inputs and on-screen reactions feels more immediate, which is critical for competitive shooters and fighting games where split-second decisions matter.
Interpolation and the "Soap Opera Effect"
Televisions often use 120 Hz technology not to match game performance, but to enhance broadcast content. Because standard movies run at 24 fps and television shows at 30 fps, manufacturers insert extra frames through a process called interpolation to match the 120 Hz refresh rate. This creates an ultra-smooth look that eliminates the cinematic "judder" but results in the "Soap Opera Effect," where film appears unnaturally sharp and video-like. For gaming, however, this processing is usually less beneficial, as the goal is to preserve the authenticity of the developer's intended frame rate rather than artificially inflate the number of displayed images.
