G-SYNC 101: External FPS Limiter HOWTO


In-game vs. External Framerate Limiters*

*As of Nvidia driver version 441.87, Nvidia has made an official framerate limiting method available in the NVCP; labeled “Max Frame Rate,” it is a CPU-level FPS limiter, and as such, is comparable to the RTSS framerate limiter in both frametime performance and added delay. The “Nvidia Inspector: 2> Frame Delay” setup detailed further below is legacy, and does not apply to the “Max Frame Rate” limiter, the setup of which is also now detailed below it.

As described in G-SYNC 101: In-game vs. External FPS Limiters, In-game framerate limiters, being at the game’s engine-level, are almost always free of additional latency, as they can regulate frames at the source. External framerate limiters, on the other hand, must intercept frames further down the rendering chain, which can result in delayed frame delivery and additional input lag; how much depends on the limiter and its implementation.

In-game framerate limiters, however, aren’t available in every game, and while they aren’t required for games where the framerate can’t meet or exceed the maximum refresh rate, if the system can sustain the framerate above the refresh rate, and a said option isn’t present, an external framerate limiter must be used with G-SYNC to prevent V-SYNC-level input lag instead.

RTSS is a CPU-level FPS limiter, and introduces up to 1 frame of delay, whereas Nvidia Inspector uses a driver-level FPS limiter, which introduces 2 or more frames of delay. See G-SYNC 101: In-game vs. External FPS Limiters for complete details, along with input latency tests comparing the two external solutions against an in-game limiter.

RivaTuner Statistic Server: <1 Frame Delay

RTSS is available standalone here, or bundled with MSI Afterburner here.

If only a framerate limiter is required, the standalone download will suffice. MSI Afterburner itself is an excellent overclocking tool that can be used in conjunction with RTSS to inject an in-game overlay with multiple customizable performance readouts.

Blur Buster's G-SYNC 101: External FPS Limiter HOWTO

RTSS can limit the framerate either globally or per profile. To add a profile, click the “Add” button in the lower left corner of the RTSS windows and navigate to the exe. To set a frame limit, click the “Framerate limit” box and input a number.

Nvidia Inspector: 2> Frame Delay

An unofficial extension of the official Nvidia Control Panel, Nvidia Inspector (download here) exposes many useful options the official control panel does not, including a driver-level framerate limiter.

Nvidia Inspector can limit the framerate either globally or per profile (more details on profile creation can be found here).

To set a frame limit, locate the “Frame Rate Limiter” dropdown in the “2 – Sync and Refresh” section, select the desired limit, and then click the “Apply Changes” button in the upper right corner of the Nvidia Inspector window.

Blur Buster's G-SYNC 101: External FPS Limiter HOWTO

As of Nvidia Profile Inspector version 2.1.3.6 and Nvidia driver branch R381 or later, a new “Frame Rate Limiter Mode” dropdown has been introduced with a “Limiter V2 – Force Off” option:

Blur Buster's G-SYNC 101: External FPS Limiter HOWTO

This option claims to reduce the limiter’s input lag; exactly by how much, and with what combination of settings, remains to be determined.

NVIDIA Control Panel: <1 Frame Delay

As of Nvidia driver version 441.87, Nvidia has made an official framerate limiting method available in the NVIDIA Control panel labeled “Max Frame Rate.”

To set a framerate limit, navigate to the “Manage 3D settings” section in the NVCP, locate the “Max Frame Rate,” entry, select “On,” set the desired limit, select “OK,” and finally select the “Apply” button after it appears in the lower right corner of the NVCP window.



3702 Comments For “G-SYNC 101”

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barry12345
Member
barry12345

Is there any explanation why my CS2 is capping at 200FPS with a 240Hz monitor?

Using Gsync + Vsync (nvcp) + reflex

With Vsync off it will uncap and I get around 300FPS so it should be able to cap at 225 like it does for everyone else?

With Vsync on the FPS is still capped at 200 even with a 225 limit set in nvcp.

barry12345
Member
barry12345

Overwatch with these settings caps at 239 instead of 225.

ItapL
Member
ItapL

In the Windows graphics settings, there’s an option for “Variable Refresh Rate.” Should I turn this on? (I’m not using an English version of Windows, so I’m not sure what the exact label says.)

My monitor has a real-time refresh rate display, but when I enable both G-SYNC and V-SYNC, it always shows the maximum refresh rate of 320 Hz in games — it doesn’t change dynamically. My G-SYNC settings are configured correctly, and V-SYNC is forced on through NVIDIA Profile Inspector.

tearxinnuan
Member
tearxinnuan

Thank you very much for your article and tutorial! I’ve set up the appropriate settings according to your article, but I still have some questions I’d like to ask!

First, my current settings are:
NVCP: G-SYNC + V-SYNC on, LLM off,
In Game: Reflex on + boost, V-SYNC off

I believe this setup is optimal for GSYNC usage. I don’t limit my frame rate using any external software or NVCP. When I enable Reflex in-game, it automatically caps my frame rate at 260 FPS (my monitor is 280Hz). I think relying solely on Reflex to limit my frame rate would be more straightforward than setting it separately, and perhaps also avoid conflicts and instability caused by multiple frame limits. Secondly, I’ve personally tested the games I play, and Reflex takes precedence over both the in-game and NVCP frame limits. That is, no matter how much I limit my frame rate, once Reflex is enabled, it caps it at 260 FPS.

I primarily play competitive games like Valve, APEX, and Overwatch, but I also occasionally play other single-player games. Then, the competitive games I play all have Reflex, so can I completely abandon all external frame limiting methods and rely solely on Reflex?

Also, regarding LLM in NVCP, should I set it on or off, or even set it to Ultra? I’m not sure if there are any advantages or disadvantages to turning LLM on, even though Reflex takes over a lot of the processing. There’s a lot of controversy online about LLM, and even NVIDA officials claim that setting LLM to Ultra will minimize V-SYCN latency.

Looking forward to your answers!

dimacbka
Member
dimacbka

Hi. I really liked this article. But I have a couple of questions. I have a new PC that gives 800 fps in cs2. How do I set up this gsync+vsync+reflex bundle correctly? My monitor is 280Hz. I’m confused, do I need to limit frames via the nvidia panel? Yesterday I turned on “delay” on Ultra and reflex+boost. In the game, the frames were around 260. With the fps_max parameter 0

mike-lesnik
Member

Hello, jorimt! My question is more about input delay than G-sync, but I decided to ask it here because I really like your style of response — simple and clear.
I don’t quite understand what role frametime plays in input delay? It is often written that frametime is the time needed to create a frame, but 60 frames of 16.6 ms each can be created by either an underloaded or overloaded GPU. On the screen, we see the same framerate and frametime in both cases, but the resulting input delay will be different…
That is, the frametime is not “the time it took the system (CPU-OS-Engine-GPU) to create the frame”, but “the time allotted for displaying the frame by the display before the next one appears”?

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