AMD FreeSync vs Nvidia G-Sync vs VSYNC – How they Work and what are the differences

Buying a good gaming monitor is one of the most crucial decisions, which in some cases, can make or break your whole gaming setup.

Since you would be looking at your monitor almost all the time when using your computer, you must buy the best monitor that renders all your fast moving game graphics perfectly.

While high refresh rates and resolutions are the main factors that buyers look for on a gaming monitor, there is another feature that we tend to overlook, and that is vertical sync and related technologies like freesync and g-sync.

The technologies covered in this post are:

• Vertical Sync - Limits Frame Rate
• Adaptive V-Sync - Limits Frame Rate, Toggles On/Off
• VESA Adaptive Sync - Variable Refresh Rate
• FreeSync - Based on VESA Adaptive Sync Standard - Variable Refresh Rate
• G-Sync - Adaptive Sync Standard - Variable Refresh Rate

Problems

Conventional display technologies suffered certain problems like:

1. Stuttering - Occurs when your computer generates frames slower than your monitor's refresh rate.
2. Screen Tearing - When your graphics card generates frames faster than your monitor's refresh rate.

If you play fast action games a lot, you probably have noticed screen tearing.

Screen tearing happens when the monitor's refresh rate is slower and cannot match that of the GPU, as a result the gpu pushes a new frame even before the previous frame has finished rendering fully.

This causes a split view displaying 2 frames simultaneously partially each. This is more noticeable when the screen display is updating rapidly, like in a FPS game.

1. Vertical Sync (VSync) - Some background

To address problems like screen tearing, manufacturers developed techniques like vertical synchronization or V-Sync.

• 1. Vertical sync is a graphics technology that lowers the frame rate (FPS) of graphics unit to match the monitor's refresh rate in order to prevent screen tearing. In this case, if you have a monitor with 60Hz, your GPU would only output 60 FPS, even if it is capable of more.
• 2. It also prevents your GPU from changing anything from your monitor’s memory until it has displayed the whole frame at once or completed its current refresh cycle.

The Half FPS problem

Vsync will keep lower the graphics adapter or systems' FPS to match the refresh rate of the monitor.

However, if the video card cannot maintain that FPS, it will be dropped to half the monitor's refresh rate. So if the monitor is 60hz, the graphics card will drop to 30hz.

If your video card cannot even maintain that FPS rate then is will be further dropped to quarter of the monitor's refresh rate. This will be 15 hz for example.

This dropping of fps to half values like 30 hz is commonly seen when playing graphics intensive games. When the on screen graphics is gpu intensive the fps will start toggling between half the monitor's refresh rate. For example the gpu will toggle between 60hz and 30hz across the game play.

Such a half drop in FPS is caused due to double-buffering used inside VSYNC.

This might make it difficult to play fast moving games like FPS.

A better option is to leave V-Sync off, which will remove the fps toggling problem and keep it constant, but you may get a little tearing.

Lot of games have options to enable or disable VSYNC during game play.

More information on screen tearing and vertical sync
https://en.wikipedia.org/wiki/Screen_tearing

Even the vertical synchronisation technique had some inherent drawbacks. Since it limits the frame rate of the gpu to match that of monitor, it creates other problems like :

• 1. Judder
• 2. Input Lag
• 3. Inaccurate Hardware Benchmarking

The significant problem is input lag, which occurs if the graphics engine limits the FPS. Games that require precise timing and fast reaction are not able to update visuals as quickly as needed. This creates a time delay between user input and display update.

Here is a useful link if you want to test stuttering on your display:
https://www.testufo.com/stutter

2. Adaptive V-Sync

Adaptive V-Sync is a variation of V-Sync.

• 1. It turns ON V-Sync when the systems' FPS is higher than the monitor's refresh rate. So this reduces the FPS of the system.
• 2. It turns OFF V-Sync when the systems' FPS is less or equal to the monitor's refresh rate.

Now turning off vsync when fps is lower than monitor refresh rate, helps eliminate input lag, but can cause stutter or tearing.

With Nvidia Graphics Cards you can configure Adaptive VSync:
https://www.nvidia.com/en-us/geforce/technologies/adaptive-vsync/

Adaptive V-sync also has an option to lock FPS to half your monitor's refresh rate.

3. VESA Adaptive Sync

To address the above mentioned limitations of VSYNC and Adaptive VSYNC, newer technologies like FreeSync and G-Sync have been developed.
G-Sync has been developed by Nvidia and FreeSync is developed by AMD.

Both these technologies are based on "Variable Refresh Rate" also known as "Adaptive Sync".

The following whitepaper from vesa.org explains Adaptive Sync:
https://www.vesa.org/wp-content/uploads/2014/07/VESA-Adaptive-Sync-Whitepaper-140620.pdf

As seen above the duration of display of a frame in monitor can be variable based on how fast the system generates the frames. This is how variable refresh rate works.

More information on Variable Refresh Rate here:
https://en.wikipedia.org/wiki/Variable_refresh_rate

4. G-Sync - Nvidia's Adaptive Sync

G-Sync is an Variable Refresh Rate based "adaptive sync" technology that adjusts the monitor's refresh rate to synchronise with the graphics adapter's/gpu's fps.

In this mechanism, the GPU produces frames at variable durations on its own and tells the monitor when to update the display.

This eliminates all problems like stuttering and screen tearing and produces super smooth frame transitions on screen at the highest possible frame-rate.

G-Sync is a proprietory technology from Nvidia and monitor manufacturers have to pay license fees to Nvidia to implement it in their hardware. Due to this gsync capable monitors are slightly more expensive.

In the past, G-Sync monitors were not cheap and would often cost $200 more compared to non-G-Sync monitors that have the same resolution and refresh rate. However, that price premium has been reduced today to about $100.

NVIDIA uses a dedicated board equipped on a G-Sync capable monitor that controls everything on the display like decoding image input and controlling the backlighting. G-Sync also uses 768 MB of DDR3 RAM for storing previous frames from a game and compares it with the incoming frame which decreases input lag.

For a full list of G-Sync capable monitors, check out:
https://www.nvidia.com/en-in/geforce/products/g-sync-monitors/specs/

System Requirements for G-Sync

Running G-Sync requires a few compatible hardware which we have conveniently listed below.

Desktops : For desktop PCs, your computer should have at least an NVIDIA GTX 650Ti BOOST or newer, and a graphics driver version R340.52 or higher.

Laptops : Laptops with built-in G-Sync displays should be equipped with at least a GTX 900M series graphics card with a driver version R352.06 or higher.

On the other hand, if you plan to connect your laptop to a G-Sync capable monitor, you should also have a GTX 900M series card but with a driver version R340.52 or higher.

G-Sync Technology Variants

G-Sync capability is implemented into monitors in 3 different ways from basic to advanced, namely G-Sync Compatible, G-Sync, G-Sync Ultimate.

More Details here:
https://www.nvidia.com/en-in/geforce/products/g-sync-monitors/

1. G-Sync Compatible

Monitors that are G-Sync compatible do not have the dedicated G-Sync processor but have been validated by NVIDIA to not have screen tearing and stuttering for a smooth gaming experience. G-Sync compatible monitors usually range between 24 - 88 inches when it comes to size.

• "G-Sync Compatible" monitors do not support Variable Overdrive.
• The dynamic refresh rate range of these monitors is limited starting at around 48-Hz.

2. G-Sync

G-Sync standard or simply G-Sync are monitors that have the dedicated G-Sync processor, giving you a full variable refresh rate and a gaming experience free from stuttering and tearing.

Monitors with a dedicated G-Sync processor have been tested and certified by NVIDIA for over 300+ tests to ensure the quality that screen tearing will not occur on any occasion. G-Sync Standard monitors are typically available between 23.8 - 38 inches in terms of screen size.

These monitors support Variable Overdrive.

3. G-Sync Ultimate

G-Sync Ultimate monitors have a dedicated hardware scaler chip from NVIDIA installed inside them.

These monitors are also tested and certified by NVIDIA with over 300+ tests to ensure that it won’t have any screen tearing across different titles.

G-Sync Ultimate monitors also have HDR capabilities with 1000 nits brightness to give you better graphics and light production when playing the latest triple-A titles.

Monitors with these capabilities usually range between 27 - 65 inches when it comes to screen size.

These monitors support Variable Overdrive.

5. AMD FreeSync - Based on VESA Adaptive Sync

AMD’s FreeSync technology enables its graphics cards and APUs to control display refresh rates to match your GPUs frame rate output. However, there is a catch. If your monitor can only output 60Hz, then your graphics card would still push higher frame rates which brings back screen tearing occasionally.

On the other hand, having your GPU to push higher frames on low refresh rate screens helps in decreasing input lag. Unlike G-Sync, FreeSync does not require monitors to have a dedicated FreeSync board but instead takes advantage of VESA’s adaptive sync technology.

More details about FreeSync can be found on AMD official website:
https://www.amd.com/en/technologies/free-sync-faq

FreeSync Variants

1. FreeSync
2. FreeSync Premium
3. FreeSync Premium Pro

System Requirements for FreeSync

If you want to use FreeSync, you would need an AMD APU or GPU that is FreeSync compatible. Luckily, all AMD graphics cards starting from the 2nd iteration of Graphics Core Next like the Radeon HD 7790 or newer versions support FreeSync.

FreeSync is also compatible with NVIDIA graphics cards, unlike G-Sync which is great for a more flexible gaming setup.

In its early stages, FreeSync was only supported for monitors with DisplayPort 1.2a and used VESA’s adaptive sync technology. However, FreeSync compatibility for HDMI 1.2+ and HDMI 2.1+ has also been added for a wider range of supported monitors.

List of FreeSync compatible monitor can be found at amd website:

https://www.amd.com/en/products/freesync-monitors

How to Enable FreeSync?

Now, to enable the feature, simply plug in your FreeSync capable monitor using a DisplayPort 1.2a or HDMI port to your GPU and open AMD Radeon Software. Radeon FreeSync should be the first option that you would see on the main screen, simply turn it on and you are good to go.

On the other hand, for those who are using NVIDIA graphics cards, you can use G-Sync on a FreeSync monitor by simply enabling G-Sync on the NVIDIA Control Panel, even if you are connected to a FreeSync monitor. However this might not work with certain monitors.

FreeSync vs G-Sync - Which one is better ?

There are 2 pieces hardware where the technologies are implemented:

1. The Graphics Card/GPU
2. The Monitor Itself

The performance of freesync or gsync would largely depend on the monitor and the supported range of dynamic refresh rates. Both Nvidia and AMD provide list of compatible monitors and details on what features are supported on each monitor model.

For example some freesync monitors will support free sync only for a smaller range of refresh rates and not upto the maximum refresh rate.

Both FreeSync and G-Sync aim to solve the same set of problems like stuttering, tearing, input lag, ghosting, corona-effect etc.

Features like Low Frame Rate Compensation and Variable Overdrive largely depend on the monitor to run properly. If the monitor supports these features that FreeSync would use them to further improve performance.

G-Sync and FreeSync are both adaptive sync technologies. Both synchronize your monitor and GPU to output the same frames, but there are a few differences that may be a deciding factor on which you should select.

Differences

1. G-Sync is more expensive.

FreeSync technology is royalty free, whereas G-Sync has licensing fees for monitor manufacturers. As a result G-Sync monitors are slightly more expensive.

The G-Sync Ultimate monitors have a dedicated hardware scaler from Nvidia installed in them for best performance, which makes them the most expensive.

2. FreeSync support is wider

Since FreeSync use the existing VESA compliant scalers that is already present in most modern monitors, the support and availability is much wider.

3. G-Sync has wider refresh rate range

Looking at the list of G-Sync compliant monitors we can tell that the "G-SYNC" and "G-SYNC ULTIMATE" monitors have a very wide range of dyanmic refresh rates starting from 1 Hz upto the maxium refresh rate of the monitor.

Whereas FreeSync monitors have a limited range of refresh rates from about 40-48 Hz upto the maxium refresh rate.

This might give G-Sync some performance edge when rendering very low frame rates.

4. Better Variable Overdrive support in G-Sync Ultimate monitors

Variable overdrive is a feature that prevents ghosting during fast changing graphics on screen.

More details about Overdrive can be found here:
https://blurbusters.com/faq/lcd-overdrive-artifacts/

At the moment monitors "G-Sync Ultimate" monitors seem to have the best support for Variable Overdrive.

On the Freesync side there most monitors only have Static/Dynamic Overdrive which does not fully solve the problem of ghosting. There is a useful reddit thread that discusses this in details:

https://www.reddit.com/r/ultrawidemasterrace/comments/alrlyv/variable_overdrive_gsync_vs_freesync/

Can FreeSync and Gsync hardware work with each other ?

The answer to this question is a bit complicated. Both technologies are exclusive and not supposed to work with each other.

For example you trying to use a Nvidia graphics card with gsync with a monitor that supports only freesync.

1. Modern Nvidia GPUs are able to support FreeSync via VESA Adaptive Sync standard so you can use them with a monitor that has only FreeSync support.

2. There are monitors that are marked as "G-Sync Compatible" and also support "VESA Adaptive Sync" which is the same as basic FreeSync. So these monitors will work with both Nvidia G-Sync GPUs and AMD FreeSync GPUs.

Check the list here: https://www.nvidia.com/en-in/geforce/products/g-sync-monitors/specs/

However AMD GPUs would generally not be able to use G-Sync features in monitor that have only G-Sync.

So the best solution is to make sure that you match your graphics card with the monitor for best compatibility and performance.

Conclusion

Overall G-Sync with the best hardware is slightly better in performance than FreeSync.

However given the significant price difference, often times its a lot better choice to go with FreeSync.

Even if you are a competitive gamer who plays FPS titles like CS:GO, FreeSync will actually deliver high quality graphics that is stutter and tear free.

However, if you are fond of the latest triple-A titles with stunning graphics like Shadow of the Tomb Raider, go ahead and spend your hard-earned money on a G-Sync monitor like ASUS TUF VG27AQ that also has a 165Hz refresh rate.

Now, for those who are looking for a budget option to experience adaptive sync technology, we suggest that you go for team red and get a FreeSync monitor. For around $150 to $300, you can get a decent gaming monitor like the MSI Optix 2020 and AOC C27G1.

Finally, this would all still depend on the graphics card that you are using.

If you already have an NVIDIA graphics card, you can just go for a "G-SYNC Compatible" monitor that supports VESA Adaptive Sync. Such monitors can work with both Nvidia G-SYNC graphics cards as well as AMD Freesync cards and deliver adaptive sync features.

Links and Resources

Wikipedia page on Freesync:
https://en.wikipedia.org/wiki/FreeSync