What is VSync and What Does it Do?

What is VSync
If you’ve gone into your favorite game’s graphics settings recently, you may have noticed a featured called VSync and you may be wondering what it is and whether or not you should turn it on, or leave it off.

VSync (or vertical sync) is a feature that attempts to help your graphics card and monitor to operate at a rate that is conducive to providing smoother gameplay. However, before you can understand what VSync is and whether or not you should be turning it on in your games, you should first understand what screen tearing is.

Screen Tearing

In computers, the graphics processing unit (GPU) is responsible for sending the necessary data to the monitor that tells the monitor what color to make each individual pixel on its screen. To you, all of those individual pixels will form a single image (or frame). And, thousands of those frames played in rapid succession will appear to you as a video or the motion in a game.

Also Read: GPU vs Graphics Card: What’s the Difference?

Most monitors operate at a fixed refresh rate. This means that over a given period of time, a monitor will show a set number of images (frames) on the screen. Most modern monitors operate with a 60Hz refresh rate, which means that every second they cycle through 60 different images (frames.)

GPUs, however, do not operate at a fixed rate. When you’re gaming, different scenarios will require more processing power, and so the GPU will not be able to send the necessary data to your monitor in as quick of a manner. And, the more powerful the GPU you have, the faster it can send data to your monitor, which results in a higher framerate.

However, since monitors typically operate at a fixed refresh rate, the monitor cannot refresh fast enough to keep up with all of the data that the GPU is send it. When this happens and depending on how fast the GPU is sending data to your monitor, you might see what appears to be a “torn” image. This is called screen tearing.

What Does VSync Do?

To combat screen tearing, developers came up with a solution called Vertical Sync. Essentially, what Vertical Sync (or VSync) does, is to force your graphics card to operate at a rate that is no higher than your monitor’s refresh rate.

So, now, instead of your GPU producing frames at a much higher rate than your monitor can refresh the screen, your GPU will be capped at a rate that matches your monitors refresh rate. So, for instance, if you are getting 100 FPS in a game on a 60Hz monitor and you turn on VSync, instead of your GPU sending 100 frames per second to your monitor, it will wait for a given period of time to send each frame to your monitor so that it matches the monitor’s 60 frames per second output.

This helps alleviate screen tearing for the most part. However, VSync is not without its own issues.

The Negative Impact that Turning VSync On Can Have

The main problem with VSync is that, with a 60Hz monitor, it isn’t guaranteed that your graphics card will always be able to maintain a consistent 60-frames-per-second output. For instance, if you’re playing a demanding game and you enter a particularly demanding situation where your GPU must work harder to produce the frame(s), your GPU may drop to a rate that is lower than 60 FPS.

When this happens, your GPU will again become out of sync with your monitor as it won’t be able to match the monitor’s refresh rate. When your GPU operates a rate that is slower than your monitor’s refresh rate, depending on how big of a difference there is between the two, you could run into problems with screen stuttering.

Also Read: Response Time vs Refresh Rate: What’s the Difference?

Screen stuttering occurs when your monitor refreshes at a rate that is higher than your GPU can send it a new frame. In these instances, from your point of view, the game seems to stutter or skip or appear choppy. And, this is really the result of your monitor skipping over frames that aren’t yet ready to be displayed.

So, is VSync Worth It?

Despite the fact that VSync can result in screen tearing if your GPU can’t maintain a framerate that matches (or exceeds) your monitor’s refresh rate, it can still be useful for some. For instance, if you have a solid graphics card and you mainly play non-demanding games where you are able to achieve a high framerate and you’ve noticed screen tearing as a result, you would benefit from turning VSync on.

On the other hand, if you have a budget-friendly graphics card and/or you are playing more demanding games and you are getting a framerate that is similar to or below your monitor’s refresh rate, turning VSync on could result in screen stuttering.

So, whether or not you should turn VSync on depends on what kind of monitor you have, what kinds of games you play, and what kind of graphics card you have. If you’re playing non-demanding games and/or you have a high-end graphics card, it might make sense to turn VSync on. If you’re playing more demanding games and/or you have a lower-end graphics card, you might want to turn VSync off.

It should also be noted that there is newer technology that helps to eliminate both screen tearing and screen stuttering…

FreeSync and G-Sync: Better Options to Eliminate Screen Tearing and Stuttering

While VSync can help eliminate screen tearing, it still doesn’t solve the fundamental flaw that exists between monitors and GPUs. And, that is that, even with VSync turned on, the monitor still operates at a fixed rate, while the GPU still operates at a variable rate (with the exception being that that rate for a GPU is capped when VSync is turned on.)

However, NVIDIA’s G-Sync technology and AMD’s FreeSync technology (and adaptive sync technology as well) have provided a solution to this fundamental flaw. And, that is that they force your monitor and GPU to operate at the same rate.

So, if you have a G-Sync monitor that has a 144Hz refresh rate and your GPU is only outputting frames at a rate of 75 FPS, then your monitor’s refresh rate will drop down to a 75Hz refresh rate. This will prevent both screen tearing and screen stuttering to occur and is a much better option than using vertical sync.

However, just like VSync, variable refresh rate technologies aren’t without their flaws as well. However, we have covered those in our posts, Is G-Sync Worth It? and Is FreeSync Worth it? And, if you want to see how the two technologies stack up against each other to help you decide which type of variable refresh rate option you want, check out our guide on G-Sync vs FreeSync.

*Just note that, if you’re building a new gaming PC, the hardware you choose may play a determining role in which technology you can use. If you opt for a configuration that includes an AMD graphics card, you can only use a FreeSync monitor. Although, if you go with an NVIDIA graphics card, you can pair it with certain FreeSync displays.

Hey, I’m Brent. I’ve been building PCs and writing about building PCs for a long time. Through TechGuided.com, I've helped thousands of people learn how to build their own computers. I’m an avid gamer and tech enthusiast, too. On YouTube, I build PCs, review laptops, components, and peripherals, and hold giveaways.

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