NVIDIA G-SYNC Practical User Guide

Since many people have doubts/certainties about the correct functioning and setting of the G-SYNC, I thought it appropriate to create this dedicated thread to discuss this technology. Tips and suggestions are, of course, welcome.

Contents index

  • 1) What is
  • 2) How it works
  • 3) How to exploit it
  • 4) How to configure it
  • 5) Opinions and personal experience

1) What it is

NVIDIA G-SYNC monitor technology is an “adaptive synchronization” technique that eliminates or at least significantly reduces:

a) Input lag. G-SYNC monitors provide minimal delay between keyboard commands and on-screen actions. b) Tearing (image tear/shake). c) Stuttering (image skip/shake).

Example of stuttering (audible, of course, only with a video).

Example of tearing.

The PC gaming experience becomes much more fluid, fast and responsive. In fact, G-SYNC dynamically aligns the display refresh rate to the GPU frame rate. Monitor refresh is not a limit and supports speeds from 0 Hz up to the maximum allowed by the monitor panel. NVIDIA is working with panel manufacturers to offer the widest range of high-speed panels on the market, from 60Hz to 240Hz.

G-SYNC monitors incorporate an NVIDIA-developed hardware module that not only drives G-SYNC in the strictest sense, but also replaces the GPU scaler (when the monitor is connected via DisplayPort, see below). This chip also manages a variable overdrive that eliminates the wake effect, predicting the next frame and adjusting the overdrive parameters of the monitor screen itself.

Finally, the G-SYNC HDR (High Dynamic Range) reproduces a very wide range of colors with extremely intense brightness for vivid graphics.

2) How it works

Since their first release, monitors have always had fixed refresh rates - typically 60 Hz. But due to the dynamic and variable nature of PC games, GPUs render frames at variable speeds. When the GPU tries to synchronize with the monitor, persistent tearing occurs. Enabling V-SYNC (Vertical-SYNC) eliminates tearing but causes increased latency and stuttering.

G-SYNC is able to eliminate this compromise, perfectly synchronizing the display with the GPU, regardless of frame rate, resulting in a world-class gaming experience.

But what are the benefits of G-SYNC over V-SYNC?

With V-SYNC active, the GPU and display are synchronized so that the former sends rendered frames per second at a fixed rate (60 times per second on a 60 Hz refresh rate monitor). There are two disadvantages associated with using V-SYNC: 1) Stuttering, as the GPU may render frames at a rate less than one frame every 1/60 seconds (or 60 FPS, frames per second). 2) Input lag, since the input response is fixed and limited to 1/60 seconds.

G-SYNC monitors resolve these disadvantages by accepting and displaying frames on screen as soon as they are rendered by the GPU. This results in a smoother gaming experience and minimized input lag.

The G-SYNC operating range of any monitor that supports this technology is always between 30 Hz - maximum monitor refresh rate (60, 75, 144, 165, 240 Hz, depending on monitor specifications). But what happens when the GPU is operating outside this range? There are two possible cases, of course.

a) The GPU can generate more FPS than the maximum monitor refresh rate. Please refer to paragraph 4) for a full explanation.

3) How to exploit it

Using the G-SYNC is very simple. The hardware and software required are as follows:

a) An NVIDIA GeForce GTX 650Ti BOOST (Kepler architecture) or higher/newer GPU. b) A compatible G-SYNC monitor. c) A cable with DisplayPort (DP) 1.2 protocol support. It is usually supplied with the monitor; it is always advisable to use the cable provided by the monitor manufacturer, or in case of a good quality cable, especially for monitors with high refresh rate (>144 Hz). d) Windows 7, 8, 8.1 or 10. e) R340.52 or newer drivers.

At this point simply connect the DP input of the monitor (generally in G-SYNC monitors there is only one DP input, so you can’t go wrong) with a DP output of the video card using the available cable. If NVIDIA drivers are already installed in your system, the G-SYNC should be active immediately. To be sure, simply go to the NVIDIA driver control panel and under “Configure G-SYNC” check “Enable G-SYNC for full screen mode”. Please note that although with the latest drivers you can also use G-SYNC in window mode, it is in full screen mode that the technology delivers the best performance.

b) The GPU generates less than 30 FPS. In this case, the dedicated chip installed in the monitor will operate the display at a refresh rate that can be up to 4 times higher than the FPS generated by the GPU. For example, if the GPU generates 25 FPS, the monitor will run at a frequency of 50 Hz, re-visualizing the same frame for 2 cycles. If the GPU generates 7 FPS, the monitor will work at 28 Hz (x4). For obvious reasons, below 7 FPS this “trick” no longer works. Clearly, this mode is not the ultimate panacea and does not make images smoother than the GPU can do, but it does prevent excessive tearing and stuttering. It goes without saying that you should better adjust your graphics settings or update your GPU if it cannot work at more than 30 FPS, as the G-SYNC is not designed to work under these extreme conditions.

It is also worth checking that the refresh rate of the monitor is correctly set to the maximum value supported by the panel. To do so, go to “Change Resolution” and check that the resolution and refresh rate are set correctly according to your monitor’s specifications.

4) How to configure it

The procedure in paragraph 3 is sufficient to use the G-SYNC without problems. However, via the NVIDIA driver control panel, you can make additional configurations to adapt the G-SYNC operation to your specific needs. Below are the steps you can take on the control panel.

1) In the first item “Configure image settings with preview” select “Use advanced 3D image settings” and press “Apply”.

https://i.imgur.com/X55WZCng.jpg

2) Under “Configure 3D Settings”, “Global Settings”, check that “Monitor Technology” is set to “G-SYNC”.

3) Under “Configure 3D Settings”, “Global Settings”, verify that “Preferred Update Rate” is set to “The highest available” (see figure above).

4) At this point, you should focus on “Configure 3D settings”, “Global settings”, “Vertical synchronization”. Although this item may suggest a V-SYNC configuration that has little to do with G-SYNC, in reality it allows you to manage the monitor behavior in case the FPS generated by the GPU is higher than the maximum monitor refresh rate, i.e. the upper limit of G-SYNC operation (which, it is worth remembering, is always in the range 30 Hz - maximum monitor refresh rate). For example, considering a G-SYNC monitor with a maximum refresh rate of 144 Hz, the settings discussed here apply when the GPU is capable of processing more than 144 FPS.

Having said that, the possibilities are as follows (of course the G-Sync must be active). Please refer to the figure above.

a) V-SYNC active. This means that the GPU will never generate more FPS than the maximum monitor refresh rate (i.e., never more than 144 FPS for a monitor with a maximum refresh rate of 144 Hz). As long as the FPS are lower than the maximum monitor refresh rate, the G-SYNC will work as expected. There is no tearing or stuttering under any circumstances. If the GPU is able to generate more FPS than the maximum monitor refresh rate, the G-SYNC is turned off and the classic V-SYNC is turned on. This can lead to increased input lag, meaning that the GPU could potentially generate more FPS which would further reduce the input lag. Not that at 144 FPS (or in general the FPS corresponding to the maximum refresh rate of the monitor) the input lag is high, quite the opposite, but some players might still want the maximum possible benefit from this point of view. The mode just described is useful in order not to make the GPU work more than it should, making it unnecessarily generate frames that the monitor would not be able to display anyway. This, of course, saves energy and the GPU temperatures are lower when the GPU and monitor are working at 144 FPS/Hz respectively.

b) V-SYNC disabled. The GPU always works 100% (during 3D processing, of course, not in general), generating the maximum possible number of FPS in each scene. As long as the generated FPS are lower than the maximum monitor refresh rate, the G-SYNC is active and works as expected, eliminating tearing and stuttering. Input lag is reduced. When the FPS are higher than the maximum monitor refresh rate, the G-SYNC turns off, no stuttering, but tearing. Input lag is reduced to the minimum possible for each rendered scene. This is a useful setting only for those who want as little input lag as possible, in all conditions, at the price of tearing, though.

c) Fast (FastSync active). The GPU always works 100% (during 3D processing, of course, not in general), generating the maximum possible number of FPS in each scene. As long as the generated FPSs are lower than the maximum monitor refresh rate, the G-SYNC is active and works as expected, eliminating tearing and stuttering. Input lag is reduced. When the FPSs are above the maximum monitor refresh rate, the G-SYNC turns off and the NVIDIA “FastSync” mode comes into play. When FastSync is on, you still have no stuttering or tearing, input lag is reduced but not as in case b). It makes sense if you play online and want to have low input lag without losing the benefits of zero tearing. It more or less combines the advantages of settings a) and b). It might give problems with some games, so try it case by case.

5) Opinions and personal experience

In this concluding paragraph, I wanted to try to describe “in words” the experience you can expect from a monitor with G-SYNC active, since images/videos are certainly not enough to understand its full potential. Two premises are necessary, in any case.

1) The perception of tearing/stuttering/input lag is completely subjective. Some may notice these “defects” immediately, others not at all, others only in certain circumstances. The experience I report below is personal and, therefore, not generalizable for anyone. 2) The only incontrovertible way to really understand how G-SYNC works is to try it in person, with one’s own eyes.

Having said this, I can try to describe the quality leap I had going from a “classic” monitor with fixed refresh rate at 60 Hz to a G-SYNC with maximum refresh rate of 165 Hz (Dell S2417DG). In games, what I immediately noticed is an incredible feeling of fluidity, combined with the total absence of trails. This, mind you, applies in general, both at high FPS and not (obviously always with a certain margin above 30 FPS). To make a quick and effective comparison, I can say without any problem that 60 FPS with G-SYNC active “look” much smoother than the classic 60 FPS “captured” with V-SYNC. Completely another story. At stake everything becomes clearer and easier to identify. In the most frantic titles, you have more awareness of what is happening, making the experience much more immersive. In addition, even considerable variations in FPS (for example, a sudden change from more than 100 FPS to 60 or less FPS) are not at all noticeable, and often you can only notice this using software that shows FPS in OSD.

Even compared to the case of V-SYNC deactivated or “tricks” like playing in a window without borders (which allows neither tearing, nor stuttering, nor increased input lag even without varaible refresh), the improvement in my case was absolutely evident. Personally, using one of the two techniques just mentioned never gave me a good feeling of fluidity, probably because my eyes do not “digest” well the misalignment between generated FPS and displayed Hz. I have always considered the best solution to activate the V-SYNC and play with constant FPS equal to the monitor refresh rate. But as mentioned above, again the G-SYNC was better, from my point of view.

Let me conclude by talking about input lag. Personally, I’ve never been very sensitive to this issue, so I couldn’t give an opinion on it. Probably the fact of not playing online never made me worry too much about this “problem”.


c) FAQ

Q: What increase in performance can I expect from G-SYNC technology? A: G-SYNC ensures that each frame rendered by the GPU is displayed in perfect sync from the monitor, up to its maximum refresh rate, but in no way increases the speed at which the GPU is able to render each frame.

Q: How does the G-SYNC work with SLI (multi NVIDIA GPU) configurations? A: The G-SYNC is actually handled by the GPU connected to the compatible monitor. SLI configurations work exactly like single GPU configurations.

Q: Does the G-SYNC work with all games? A: Yes. However, some (thankfully rare) games may experience problems with G-SYNC on, so in these cases it is advisable to turn it off. NVIDIA ensures that problematic games will be handled automatically by the graphics drivers, leading to automatic deactivation of G-SYNC for such games.

Q: What is the impact of G-SYNC on input latency? A: Unlike V-SYNC, G-SYNC has a significantly lower impact on input latency, making it a great choice for first-person shooters and competitive online games. However, if you want to have as little input lag as possible, please refer to paragraph 4).

Q: What are the hardware/software requirements for G-SYNC? A: In addition to a compatible monitor, you will need a DisplayPort 1.2 cable connected directly to the GPU. G-SYNC runs on an NVIDIA GeForce GTX 650Ti BOOST or newer. Supported operating systems are Windows 7, 8, 8.1, and 10. You need drivers from version R340.52 or newer.

Q: Do G-SYNC monitors work with competitive (i.e., AMD) GPUs? A: Yes, but all the benefits associated with G-SYNC technology are lost. The monitor will behave like a “classic” monitor with a fixed refresh rate (equal to the maximum supported by the panel).

Q: What are the minimum requirements for G-SYNC notebooks? A: The notebook must be explicitly G-SYNC compatible, i.e. it must adopt a dedicated panel and meet the following requirements. Compatible GPUs: GeForce GTX 980, 980M, 970M or 965M (SLI configurations of these GPUs are supported). Windows 7, 8, 8.1 and 10. R352.06 or newer drivers.

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