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Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 15 Aug 2020, 11:17
by jorimt
Defox wrote:
15 Aug 2020, 10:46
There was one more question.
To get lower input latency in "Low Latency Mode = Ultra" - we need to limit in-game FPS below 138 (in the case of a 144 Hz monitor).
But. If there is no in-game limiter. Does it make sense to limit FPS using the nvidia control panel (as we know it increase input lag)? Will this decrease the input lag or, on the contrary, increase it?
Ultra's auto FPS limiter uses the same solution Nvidia's "Max Frame Rate" option uses, which is typically on par with the RTSS limiter in frametime performance and input lag. So if there's no in-game limiter and you don't want to use RTSS to limit the FPS below the Ultra auto-limiter (in cases you need a lower than 138 FPS limit to prevent max GPU usage), switch LLM to "On," and set the Nvidia "Max Frame Rate" option to the desired limit instead.

Again, with G-SYNC, the only known difference between LLM "On" and "Ultra," is that Ultra sets an auto FPS limit in supported games. Beyond that, they both reduce the pre-rendered frames queue in GPU-bound situations the same way via an MPRF value of "1" (with G-SYNC).

- G-SYNC + V-SYNC + LLM Ultra = MPRF "1" + auto FPS limit
- G-SYNC + V-SYNC + LLM On = MPRF "1"

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 15 Oct 2020, 06:34
by Defox
jorimt wrote:
01 Aug 2020, 09:35
Basically, if you use G-SYNC, it's safe to leave LLM set to "On."
In a recent video of Battle(non)sense about "NVIDIA Reflex", I noticed that it recommends setting the low latency mode to "Off". Why not "On"? If I am correctly aware, then the "On" value forces the maximum number of prepared frames to 1, which will give us confidence that the game will not prepare more than 1 frame.

Are there any explanations and assumptions why he recommends installing it "Off"?

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 15 Oct 2020, 09:22
by jorimt
Defox wrote:
15 Oct 2020, 06:34
In a recent video of Battle(non)sense about "NVIDIA Reflex", I noticed that it recommends setting the low latency mode to "Off". Why not "On"? If I am correctly aware, then the "On" value forces the maximum number of prepared frames to 1, which will give us confidence that the game will not prepare more than 1 frame.

Are there any explanations and assumptions why he recommends installing it "Off"?
Because Reflex effectively removes the pre-rendered frames queue entirely, thus LLM has nothing to reduce. Reflex is an LLM replacement.

That said, you can leave LLM "On" globally for games that don't support Reflex, as Reflex will ignore LLM settings anyway.

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 17 Oct 2020, 10:39
by Defox
jorimt wrote:
15 Oct 2020, 09:22

Because Reflex effectively removes the pre-rendered frames queue entirely, thus LLM has nothing to reduce. Reflex is an LLM replacement.

That said, you can leave LLM "On" globally for games that don't support Reflex, as Reflex will ignore LLM settings anyway.
However, in earlier videos, when the NVIDIA Reflex did not yet exist, he still conducted tests with the LLM turned off. It seems to me in this way he misleads his audience a little (since they will just repeat after him without knowing what exactly this setting does), since some games may be configured to prepare more than 1 pre-frame, which will eventually cause additional input lag.

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 17 Oct 2020, 14:26
by jorimt
Defox wrote:
17 Oct 2020, 10:39
since some games may be configured to prepare more than 1 pre-frame, which will eventually cause additional input lag.
In GPU-bound scenarios, yes, in non-GPU-bound scenarios, almost never. That and LLM only works in some games. It doesn't work in DX12 or Vulkan at all, for instance.

LLM honestly isn't a very impactful setting when compared to other input lag reduction methods.

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 28 Oct 2020, 12:00
by TTT
jorimt wrote:
15 Aug 2020, 11:17
Defox wrote:
15 Aug 2020, 10:46
There was one more question.
To get lower input latency in "Low Latency Mode = Ultra" - we need to limit in-game FPS below 138 (in the case of a 144 Hz monitor).
But. If there is no in-game limiter. Does it make sense to limit FPS using the nvidia control panel (as we know it increase input lag)? Will this decrease the input lag or, on the contrary, increase it?
Ultra's auto FPS limiter uses the same solution Nvidia's "Max Frame Rate" option uses, which is typically on par with the RTSS limiter in frametime performance and input lag. So if there's no in-game limiter and you don't want to use RTSS to limit the FPS below the Ultra auto-limiter (in cases you need a lower than 138 FPS limit to prevent max GPU usage), switch LLM to "On," and set the Nvidia "Max Frame Rate" option to the desired limit instead.

Again, with G-SYNC, the only known difference between LLM "On" and "Ultra," is that Ultra sets an auto FPS limit in supported games. Beyond that, they both reduce the pre-rendered frames queue in GPU-bound situations the same way via an MPRF value of "1" (with G-SYNC).

- G-SYNC + V-SYNC + LLM Ultra = MPRF "1" + auto FPS limit
- G-SYNC + V-SYNC + LLM On = MPRF "1"
I've just noticed on Destiny 2 playing with Gsync on, Vsync on via NCP, Null to ON. Unlocked fps in game its capping me to 225 on a 240hz monitor. So Ultra and ON now auto cap?

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 28 Oct 2020, 12:59
by jorimt
TTT wrote:
28 Oct 2020, 12:00
I've just noticed on Destiny 2 playing with Gsync on, Vsync on via NCP, Null to ON. Unlocked fps in game its capping me to 225 on a 240hz monitor. So Ultra and ON now auto cap?
G-SYNC on + V-SYNC (NVCP) on + LLM "On" should not auto limit the framerate.

Did they add Nvidia Reflex support to D2 yet? Because if it were enabled, it would do the same thing as LLM "Ultra," regardless of LLM settings (which are overridden by Reflex).

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 28 Oct 2020, 14:18
by TTT
jorimt wrote:
28 Oct 2020, 12:59
TTT wrote:
28 Oct 2020, 12:00
I've just noticed on Destiny 2 playing with Gsync on, Vsync on via NCP, Null to ON. Unlocked fps in game its capping me to 225 on a 240hz monitor. So Ultra and ON now auto cap?
G-SYNC on + V-SYNC (NVCP) on + LLM "On" should not auto limit the framerate.

Did they add Nvidia Reflex support to D2 yet? Because if it were enabled, it would do the same thing as LLM "Ultra," regardless of LLM settings (which are overridden by Reflex).
No Reflex isn't on there yet.

I've tried switching between ON and ULTRA and completely off and going back to ON it still limits it to 225.

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 28 Oct 2020, 15:23
by jorimt
TTT wrote:
28 Oct 2020, 14:18
No Reflex isn't on there yet.

I've tried switching between ON and ULTRA and completely off and going back to ON it still limits it to 225.
Is this happening in other games, or only D2? May be game-specific.

I own it, but I haven't played it in nearly a year and currently have it uninstalled (huge download size), so I can't easily test this myself.

A workaround to prevent the auto FPS limit is to disable NVCP V-SYNC (set to use 3D application setting) and enabled in-game V-SYNC for use with G-SYNC instead.

Re: NVIDIA Low Latency Mode - On or Off for less Input lag?

Posted: 28 Oct 2020, 15:57
by TTT
jorimt wrote:
28 Oct 2020, 15:23
TTT wrote:
28 Oct 2020, 14:18
No Reflex isn't on there yet.

I've tried switching between ON and ULTRA and completely off and going back to ON it still limits it to 225.
Is this happening in other games, or only D2? May be game-specific.

I own it, but I haven't played it in nearly a year and currently have it uninstalled (huge download size), so I can't easily test this myself.

A workaround to prevent the auto FPS limit is to disable NVCP V-SYNC (set to use 3D application setting) and enabled in-game V-SYNC for use with G-SYNC instead.
I'll check some other games tomorrow.

Its not actually a problem because I'm not hitting that anyway, I just noticed it capping to 225 on loading screens and remember reading about the Ultra cap on here.