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/App; labeled “Max Frame Rate,” which 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 Profile 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 Profile 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 Profile Inspector: 2> Frame Delay

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

The NVIDIA Profile 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 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/App: <1 Frame Delay

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

To set a framerate limit, navigate to “Graphics” in the NVIDIA Ap or “Manage 3D settings” in the NVCP, locate “Max Frame Rate,” select “On,” set the desired limit, and select “Apply,” or “OK,” then “Apply.“



3890 Comments For “G-SYNC 101”

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user2422
Member
user2422

In an earlier comment you mentioned that ULLM is somewhat inefficient compared to Reflex or a manual limit, if i were to use Gsync + Vsync + ULLM, would that starving of the max queued frames and the potential stutters that come with it even apply considering that ULLM is auto limiting the fps in this configuration? Like does it limit low enough to prevent this from even happening?

Also when using Gsync + Vsync and then only enabling ULLM via Inspector without setting max pre-rendered frames to 1 (which ULLM would’ve otherwise done if it was applied via NVCP or NVApp), would this then be just an auto limiter without the other effects of ULLM? I’ve tried this configuration in-game and the auto limit still applies but I’m unsure whether or not ULLM will have any other impact in this configuration.

eonjr
Member
eonjr

Hi, thank you for the guides! But I have something to ask. My laptop has a 300hz refresh rate that is also GSync compatible. I have it capped at 285 using a formula that I saw on a Reddit post a while ago (via NVIDIA APP > Max Frame Rate).

I unfortunately get this gray flickering during gaming but I can get used to it. However, what I cannot stand is, when I tried using editing software (like Adobe Premiere Pro), the flickering was also present despite me having turned off GSync specifically for that app (via NVIDIA App). Is there something I am doing wrong? What can be done to completely eliminate flickering for non-game apps?

HagenKL
Member
HagenKL

Hey, the article talks about GSync with the Module. Is the Behaviour the same for GSync Compatible (aka Freesync monitors?)

Apache3m
Member
Apache3m

Naturally, with MFG enabled, Reflex limits my FPS from 240 to 224; however, if I disable V-Sync in the Nvidia Control Panel, I hit 240 FPS with MFG on.

Mark Rejhon
Admin

It bears worth noting that 224 vs 240 is extremely small (1/224)-(1/240) = 0.3ms frametime difference. It’s more about geometrics (e.g. 200fps vs 400fps vs 1000fps) that is much more noticeable. It’s possible to have a much smoother 224fps and a much worse 240fps that looks rougher-motion than 224fps. It’s all in the microstutter/tearing mechanics, and how you prioritize visual fidelity. A great test is to strafe in CP2077 and watch for microstuttering/tearing. This is one of the ways to compare framepacing quality of VRR and capping mechanisms.

Those using VRR and framegen are often looking to improve smoothness without prioritizing on esports latency, so this is often prioritized for solo games like Witcher and CP2077. Turning off Reflex and still using VSYNC ON is another way to get 240fps with smoothness, but that increases latency dramatically on top of the latency that framegen gives, so it can veer into distraction territory.

Reflex + framegen + VRR is a good “acceptable-for-solo latency” compromise, and lagfeel can actually still feel similar to the original pre-framegen framerate (with latency countermeasured turned off).

Apache3m
Member
Apache3m

Hi – I have a setup with a 9800X3D and an RTX 5080, along with an MSI 321URX QD-OLED monitor.
Could you tell me what I should do when gaming with NVIDIA’s Frame Gen (MFG) enabled? Should I stick with the G-Sync + V-Sync + Reflex settings, or do you recommend something else?

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