Game locked at 20fps, what RTSS settings?

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hejonar
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Joined: 17 Jan 2019, 08:31

Game locked at 20fps, what RTSS settings?

Post by hejonar » 12 Feb 2019, 02:39

I wanted to test RTSS Vsync-on method, as described here: https://www.blurbusters.com/howto-low-lag-vsync-on/

The game I am testing on is locked to 20fps, there is no way of changing it. My monitor is just plain 60Hz LCD without any special sync option. The game pretty much requires vsync as tearing and other artifacts are common without it, at least on my screen. My questions is, which value should I enter in RTSS "Frame Limit" box, would it be 20, as game is already running much below 60Hz or perhaps setting it to 19.993 would be better? My monitor according to tests runs at 60.0000Hz, with +/- variation of 0.0005Hz.

I would try scanline sync but as I understand 20fps is too low as it would require x/3 setting which is unobtainable. Perhaps one day such option will be available through config file :lol: .


By the way, the game is ran through dgvoodoo2 which is how I am forcing vsync but I could also use NVidia Control Panel or both. Which one would be better?

Sparky
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Re: Game locked at 20fps, what RTSS settings?

Post by Sparky » 12 Feb 2019, 06:41

If the game is locked at 20fps, basically nothing you do will improve latency. The point of the adding a cap is to keep framerate under refresh rate(thus reducing buffering throughout the render pipeline), but you're already 40fps below your refresh rate, so it's not helping anything.

hejonar
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Re: Game locked at 20fps, what RTSS settings?

Post by hejonar » 12 Feb 2019, 06:56

Using RTSS at least stabilizes frametimes.

Sparky
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Re: Game locked at 20fps, what RTSS settings?

Post by Sparky » 12 Feb 2019, 14:34

hejonar wrote:Using RTSS at least stabilizes frametimes.
Not without adding latency. At 20fps, 1 frame of latency is 50ms, not a good tradeoff.

hejonar
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Re: Game locked at 20fps, what RTSS settings?

Post by hejonar » 12 Feb 2019, 14:44

Sparky wrote:
hejonar wrote:Using RTSS at least stabilizes frametimes.
Not without adding latency. At 20fps, 1 frame of latency is 50ms, not a good tradeoff.
Fair point :idea:

What about forcing v-sync through NV Control Panel vs dgvoodoo, does it matter how I apply it to game?
I am also using some post process effects, mainly FXAA through NV Control Panel with two sharpening reShade filters to offset blur, do those add much latency and should be disabled?

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Re: Game locked at 20fps, what RTSS settings?

Post by RealNC » 12 Feb 2019, 14:44

At 20FPS, there's nothing to improve when it comes to frame pacing, IMO. It's gonna look awful no matter what you do :mrgreen:

How you apply vsync doesn't really matter, unless dgvoodo has buggy vsync.

ReShade doesn't add latency.
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Re: Game locked at 20fps, what RTSS settings?

Post by Chief Blur Buster » 13 Feb 2019, 02:27

Sparky wrote:If the game is locked at 20fps, basically nothing you do will improve latency.
An expensive workaround is you can get pretty low latency 20fps by purchasing a new monitor that uses high-Hz variable fresh rate (VRR) using G-SYNC or FreeSync.

Even 20fps GSYNC/FreeSync is lower lag (via LFC).

20fps frames are "scanned-out" in only 1/240sec on a 240Hz variable refresh monitor.
20fps frames are "scanned-out" in only 1/144sec on a 144Hz variable refresh monitor.
See videos at Understanding Display Scan-Out Lag With High Speed Video

Assuming it uses a time-based capping method (1/20sec timer) rather than a VSYNC-counting capping method (1 in 3 VSYNCs)
The only way to reduce latency further is to purchase a high-Hz VRR monitor for the latency savings of a fast frame transport.

Just enable GSYNC/FreeSync ON while forcing the game's VSYNC setting OFF (NVInspector, etc) then you'll see latency reduced a bit without adding tearing nor stutters. You get 20fps that looks like VSYNC ON, but has less latency than VSYNC ON.

If you need to reduce latency in self-capping games, don't use RTSS for self-capping games.
The 20fps game capper is its own capping behaviour.

You'll be unable to do anything about low-framerate latency, but you can at least reduce the scanout latency via
(A) eliminating "wait for vsync" latency via getting GSYNC or FreeSync; and
(B) speeding up the scanout from 1/60sec down to either 1/144sec or 1/240sec (thanks to getting a 144Hz or 240Hz monitor)
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