Nvidia Reflex causes stuttering

[Solar Field]

So, I've been playing for a couple of hours so far and something was driving me crazy.

Basically the game runs at a locked 60fps (with ~55fps 1%low), but it never felt smooth. Every time I was moving the camera I could tell something was wrong, it was a stutter mess.

After spending an hour testing each option, I finally realised that turning off Reflex entirely fixed the problem. My game is finally smooth.

If MSI Afterburner (or any other app you're using to monitor your framerate) is reporting 60 (or your target framerate) but still doesn't feel like it, I would suggest to turn Reflex Off.

Other than that, the game runs very well and feels properly optimised (at least for my modest 5700X with an RTX 4070).

Enjoy o/

Edit: All drivers up to date (551.86), VRR display and G-Sync On, frame cap via RTSS: 60fps

[Neo Vg]

Reflex "on" should work fine, only "on + boost" seems to be bugged.

And yes, game is properly optimized, no annoying stuttering and very stable frame times. What a welcome diversion, a PC port that actually works. :D

[Phaz]

Same issue for me, Turning Reflex to On or Boost causes uneven frametimes and a very choppy feeling. This also makes FrameGen unusable.

[Solar Field]

Originally posted by Neo Vg:

Reflex "on" should work fine, only "on + boost" seems to be bugged.

And yes, game is properly optimized, no annoying stuttering and very stable frame times. What a welcome diversion, a PC port that actually works. :D

I guess it's gonna be different for everyone but "Reflex ON" causes stuttering for me (especially noticeable when moving the camera). Turning it off solved the issue, so I thought I would let people know just in case others are losing their minds over this (like I did).

[Kaldaien]

This is how Reflex works, BTW.

If you install Special K, open its Latency Analysis under Framerate Limiter > Advanced. It has very detailed Reflex info, and various override settings available.

Only the experimental version has that functionality though, the normal website release is 6 months old and lacks it.

[Phaz]

Reflex (and by extension FrameGen) is completely pointless if it introduces major uneven frame pacing. In other games it doesn't do that. This is not normal behaviour.

[Kaldaien]

Originally posted by Phaz:

Reflex (and by extension FrameGen) is completely pointless if it introduces major uneven frame pacing. In other games it doesn't do that. This is not normal behaviour.

It's less of a problem than you'd think.

The framerate limiter runs -after- the image is submitted for display output. Reflex is designed first and foremost for VRR. So what it's doing with those uneven frames (and trust me, the "unevenness" depends on the measurement technique you use) is adding a delay before the start of the next frame to eliminate queued frames.

SK has 3 different frametime calculation methods you can use.

Frame Submission (appears smooth on limiters designed for fixed-refresh)
Frame Start (appears smooth on limiters designed to reduce latency)
Frame Pace (appears smooth when SK's framerate limiter is active)

Depending on which method you use, Reflex can look really bad. But you have to remember it's designed for VRR. Most frametime measurement is designed for fixed-refresh displays.

---

Both RTSS and Special K have these alternate methods for measuring frametime. You need to pick a VRR-oriented frametime measurement method if you want to correctly analyze Reflex, otherwise it just looks like a stuttering mess.

[Phaz]

I am using it with VRR, but it feels completely unsmooth. That is my primary issue. Besides that, I see with RTSS that frametimes are uneven. The frametime graph becomes a thick area instead of a thin line, suggesting that a fast and a slow frame are continusouly alternating each other. I'm not sure if that measurement is correct, but in any case case it feels and visually is, very unsmooth. So much so that it's unusable.

So yeah, this is a big problem.

[Neo Vg]

Originally posted by Phaz:

The frametime graph becomes a thick area instead of a thin line, suggesting that a fast and a slow frame are continusouly alternating each other.

I also noticed that effect on the frame time graph. It still feels very smooth though. I do get a weirdly unsmooth experience however when using DLSS (any quality setting) instead of DLAA, mainly while being in busy areas like cities. Camera movement feels choppy somehow.

[Solar Field]

Originally posted by Kaldaien:

This is how Reflex works, BTW.

If you install Special K, open its Latency Analysis under Framerate Limiter > Advanced. It has very detailed Reflex info, and various override settings available.

Only the experimental version has that functionality though, the normal website release is 6 months old and lacks it.

Been using Reflex in many games and it never caused that issue.
So yeah, this is a problem.

[Solar Field]

Originally posted by Phaz:

I am using it with VRR, but it feels completely unsmooth. That is my primary issue. Besides that, I see with RTSS that frametimes are uneven. The frametime graph becomes a thick area instead of a thin line, suggesting that a fast and a slow frame are continusouly alternating each other. I'm not sure if that measurement is correct, but in any case case it feels and visually is, very unsmooth. So much so that it's unusable.

So yeah, this is a big problem.

Same issue...

I'm also using VRR and it doesn't help, but having Reflex off does fix the issue.
Could be something related to a specific hardware combo for all I know, but for now that's the only thing we can do.

[Solar Field]

Originally posted by Neo Vg:

Originally posted by Phaz:

The frametime graph becomes a thick area instead of a thin line, suggesting that a fast and a slow frame are continusouly alternating each other.

I also noticed that effect on the frame time graph. It still feels very smooth though. I do get a weirdly unsmooth experience however when using DLSS (any quality setting) instead of DLAA, mainly while being in busy areas like cities. Camera movement feels choppy somehow.

It sounds like the issue I was having. But DLSS or DLAA was giving me the same result. Reflex was the culprit for the stuttering in my case.

Guess it's different for everyone, but this is the first time I'm experiencing this issue with Reflex.

At least, if anyone else is having the same issue, it might help.

[Kaldaien]

Originally posted by Solar Field:

Originally posted by Kaldaien:

This is how Reflex works, BTW.

If you install Special K, open its Latency Analysis under Framerate Limiter > Advanced. It has very detailed Reflex info, and various override settings available.

Only the experimental version has that functionality though, the normal website release is 6 months old and lacks it.

Been using Reflex in many games and it never caused that issue.
So yeah, this is a problem.

Well, you can use Special K. Its framerate limiter will auto-configure itself to 99.5% of Reflex's internal limit so as to frame pace the game without hitting Reflex's limit.

The equation to calculate that limit is (a really weird one):

Refresh Rate - (Refresh Rate * Refresh Rate) / 3600.0

That's Reflex's target rate, you need to multiply that by 0.995 to calculate the limit to set a third-party limiter to in order to have it take precedence over Reflex.

You can certainly do all that crap by hand and plug those numbers into RTSS, but Special K makes it a hell of a lot simpler and has numerous Reflex-related overrides and analysis in the Framerate Limiter / Advanced section of its control panel.

For example, here's a game with an actual Reflex bug (has to be set to Boost mode manually or overridden in SK's override section):

https://youtu.be/2kK_OYHh2hY

[Emig5m]

I get the smoothest look and feel with Reflex off and Vsync off (I get no screen tearing) and using DLAA.

[nbean16]

Originally posted by Neo Vg:

Reflex "on" should work fine, only "on + boost" seems to be bugged.

And yes, game is properly optimized, no annoying stuttering and very stable frame times. What a welcome diversion, a PC port that actually works. :D

On isnt good either. Definitely has frametime issues.

[Kaldaien]

Originally posted by nbean16:

Originally posted by Neo Vg:

Reflex "on" should work fine, only "on + boost" seems to be bugged.

And yes, game is properly optimized, no annoying stuttering and very stable frame times. What a welcome diversion, a PC port that actually works. :D

On isnt good either. Definitely has frametime issues.

On is perfectly fine.

You need an additional framerate limiter because simply using Reflex will cap you to Refresh Rate - (Refresh Rate * Refresh Rate) / 3600.0 and you're not even hitting that framerate to begin with.

Reflex isn't a framerate limiter any more than it has to be, which is to say, it calculates the highest possible framerate that won't cause the driver to switch from VRR to normal VSYNC (using the equation above).

If you can't sustain the framerate from the equation above, then Reflex is not a frame pacer in any way shape or form.