Gsync Question

[LCDArcade]

I have two Gsync monitors now (one I've had a for a few months) but I've never truly known if I have them setup properly or how to know it's working. I have Gsync turned on in the NVIDIA control panel but what about in games. Do I leave Vsync option turned on or off?

EDIT: Also probably important to note that I run most of my games in Full-screen widowed mode(borderless)

[Netherspark]

I believe that turning V-sync on effectively overrides G-sync.

Or more accurately, Gsync is active but it's just not doing anything because Vsync is getting there first.

[Gaidax]

Vsync should be turned off.

[LCDArcade]

Thanks.
10 characters

[Life-Binder]

long read https://www.blurbusters.com/gsync/gsync101/

but it answers every question


tl;dr:

Optimal G-SYNC Settings*
*Settings tested with a single G-SYNC display on a single desktop GPU system; specific DSR, SLI, and multi-monitor behaviors, as well as laptop G-SYNC implementation, may vary.


Nvidia Control Panel Settings:

- Set up G-SYNC > Enable G-SYNC > Enable G-SYNC for full screen mode.
- Manage 3D settings > Vertical sync > On.

In-game Settings:

- Use “Fullscreen” or “Exclusive Fullscreen” mode (some games do not offer this option, or label borderless windowed as fullscreen).
- Disable all available “Vertical Sync,” “V-SYNC” and “Triple Buffering” options.
- If an in-game or config file FPS limiter is available, and framerate exceeds refresh rate:
Set 3 FPS limit below display’s maximum refresh rate (57 FPS @60Hz, 97 FPS @100Hz, 117 FPS @120hz, 141 FPS @144Hz, etc).

RTSS Settings:

- If an in-game or config file FPS limiter is not available and framerate exceeds refresh rate:
Set 3 FPS limit below display’s maximum refresh rate (see G-SYNC 101: External FPS Limiters HOWTO).

- - - Updated - - -

concerning Vsync On/Off in the NVCP

apparently there is actually a benefit to turning it On in the NVCP (and Off in the games), despite it not really kicking in as long as you are in Gsync range (~30-144 Hz)

Upon its release, G-SYNC’s ability to fall back on fixed refresh rate V-SYNC behavior when exceeding the maximum refresh rate of the display was built-in and non-optional. A 2015 driver update later exposed the option.

This update led to recurring confusion, creating a misconception that G-SYNC and V-SYNC are entirely separate options. However, with G-SYNC enabled, the “Vertical sync” option in the control panel no longer acts as V-SYNC, and actually dictates whether, one, the G-SYNC module compensates for frametime variances output by the system (which prevents tearing at all times. G-SYNC + V-SYNC “Off” disables this behavior; see G-SYNC 101: Range), and two, whether G-SYNC falls back on fixed refresh rate V-SYNC behavior; if V-SYNC is “On,” G-SYNC will revert to V-SYNC behavior above its range, if V-SYNC is “Off,” G-SYNC will disable above its range, and tearing will begin display wide.

Within its range, G-SYNC is the only syncing method active, no matter the V-SYNC “On” or “Off” setting.

G-SYNC + V-SYNC “On”:

This is how G-SYNC was originally intended to function. Unlike G-SYNC + V-SYNC “Off,” G-SYNC + V-SYNC “On” allows the G-SYNC module to compensate for sudden frametime variances by adhering to the scanout, which ensures the affected frame scan will complete in the current scanout before the next frame scan and scanout begin. This eliminates tearing within the G-SYNC range, in spite of the frametime variances encountered.

Frametime compensation with V-SYNC “On” is performed during the vertical blanking interval (the span between the previous and next frame scan), and, as such, does not delay single frame delivery within the G-SYNC range and is recommended for a tear-free experience (see G-SYNC 101: Input Lag & Optimal Settings).

Now that the FPS limit required for G-SYNC to avoid V-SYNC-level input lag has been established, how does G-SYNC + V-SYNC and G-SYNC + V-SYNC “Off” compare to V-SYNC OFF at the same framerate?

The results show a consistent difference between the three methods across most refresh rates (240Hz is nearly equalized in any scenario), with V-SYNC OFF (G-SYNC + V-SYNC “Off,” to a lesser degree) appearing to have a slight edge over G-SYNC + V-SYNC. Why? The answer is tearing…

With any vertical synchronization method, the delivery speed of a single, tear-free frame (barring unrelated frame delay caused by many other factors) is ultimately limited by the scanout. As mentioned in G-SYNC 101: Range, The “scanout” is the total time it takes a single frame to be physically drawn, pixel by pixel, left to right, top to bottom on-screen.

With a fixed refresh rate display, both the refresh rate and scanout remain fixed at their maximum, regardless of framerate. With G-SYNC, the refresh rate is matched to the framerate, and while the scanout speed remains fixed, the refresh rate controls how many times the scanout is repeated per second (60 times at 60 FPS/60Hz, 45 times at 45 fps/45Hz, etc), along with the duration of the vertical blanking interval (the span between the previous and next frame scan), where G-SYNC calculates and performs all overdrive and synchronization adjustments from frame to frame.

The scanout speed itself, both on a fixed refresh rate and variable refresh rate display, is dictated by the current maximum refresh rate of the display:

Blur Buster's G-SYNC 101: Scanout Speed DiagramAs the diagram shows, the higher the refresh rate of the display, the faster the scanout speed becomes. This also explains why V-SYNC OFF’s input lag advantage, especially at the same framerate as G-SYNC, is reduced as the refresh rate increases; single frame delivery becomes faster, and V-SYNC OFF has less of an opportunity to defeat the scanout.

V-SYNC OFF can defeat the scanout by starting the scan of the next frame(s) within the previous frame’s scanout anywhere on screen, and at any given time:


This results in simultaneous delivery of more than one frame scan in a single scanout (tearing), but also a reduction in input lag; the amount of which is dictated by the positioning and number of tearline(s), which is further dictated by the refresh rate/sustained framerate ratio (more on this later).

As noted in G-SYNC 101: Range, G-SYNC + VSYNC “Off” (a.k.a. Adaptive G-SYNC) can have a slight input lag reduction over G-SYNC + V-SYNC as well, since it will opt for tearing instead of aligning the next frame scan to the next scanout when sudden frametime variances occur.

To eliminate tearing, G-SYNC + VSYNC is limited to completing a single frame scan per scanout, and it must follow the scanout from top to bottom, without exception. On paper, this can give the impression that G-SYNC + V-SYNC has an increase in latency over the other two methods. However, the delivery of a single, complete frame with G-SYNC + V-SYNC is actually the lowest possible, or neutral speed, and the advantage seen with V-SYNC OFF is the negative reduction in delivery speed, due to its ability to defeat the scanout.

Bottom-line, within its range, G-SYNC + V-SYNC delivers single, tear-free frames to the display the fastest the scanout allows; any faster, and tearing would be introduced.