We’ve all had it happen at one point or another. You’re playing a game and every time you rotate the screen, even by only a bit, the familiar line can be seen splitting one frame from another on the screen. To some, this is only a minor inconvenience that lessens the beauty of an otherwise impressive game. For others, it can mean the difference between being on top of the scoreboard at the end of the round and being on the bottom. This split occurs because the frame rate of your game isn’t correctly aligned to your monitor’s refresh rate.
While the frame rate and refresh rate may be completely different in their respective places, they go hand-in-hand in how they relate to each other to deliver a smooth image from your video source to the screen.
Most LCD monitors sold today run on a standard 60 Hz refresh rate. This rate is determined by the speed the monitor can refresh the screen and replace a previous frame with a new image. A monitor that operates at 120 Hz, for example, will refresh the image 120 times every second, so the optimal frame rate will be some number 120 can divide into (60, 30, 20, 40, etc.).
If you’re playing a game that runs on a frame rate that doesn’t go into 60 evenly (24 FPS, for example), you may notice slight tearing in the image as you pan around quickly during gameplay.
This can be solved to some degree by turning on vertical sync, which matches your frame rate to the refresh rate of the monitor. Playing on underpowered hardware may limit your ability to properly utilize this feature unless you step the graphics quality down a notch or two. Vertical sync has been known to cause some minor delay in controls, giving you a small degree of extra latency between command and result, but for some, this is much more appealing than a screen that splits itself between frames as you pan back and forth, looking for enemies.
With television, this can become a problem when purchasing games that are optimized for a specific frame rate that isn’t directly compatible with your television’s refresh rate. While most major game and console manufacturers stick to a frame rate that is industry standard for the region where it’s set to be sold, occasional crossovers can take place. The differences between PAL (50 Hz) and NTSC (60 Hz) can make movies and videos formatted for European televisions appear fuzzy or split on a television made for the United States.
Some televisions (and monitors) have an automatic adjustment that takes place to repeat frames and interpolate information when there’s a mismatch to avoid obvious tearing. Even with this in place, the image quality may not be what the content creator intended. While there is no sure way to sync these two based on any information available on the packaging, the best rule of thumb is not to purchase retail boxes intended for a foreign audience with different video standards than the ones present in your specific region.