Input Lag with GSYNC

[SachsenPowl]

I have some questions about Input Lag and G-SYNC but found various answers...

Tl.dr to make it quick: what settings should i set for lowest possible Input Lag?
-"Games (like CoD MW2 WZ2) if fps >144 (my case 1080p) ->>>> G-SYNC + V-SYNC (NVCP)?, Ingame Limiter 141? Nvidia Limiter 141? Limiter trough ULLM Ultra (~138?), Reflex? HDR adds Lag?"
-"Games (like CoD MW2 WZ2) if fps <144 (my case 2160p) ->>>> G-SYNC + V-SYNC (NVCP)?, Ingame Limiter? Nvidia Limiter? ULLM On,Off,Ultra?, Reflex? HDR adds Lag?""
-what to set if there are other games, fps higher than refresh rate (Valorant, Quake, Unreal Tournament)?
-Does Input Lag change from native resolution to non-native?
-What if i change from 8bit to 10bit, RGB, chroma 422 etc?

Hardware is
LG 27GP950-B (latest FW) at 144Hz without OC at DisplayPort 1.4, connected with a Nvidia 2070 Super (Ryzen 5900X as CPU, 2x16GB 3800CL14 DDR4).

longer version:
I never played with G-SYNC before and tryed to get some knowledge about it but struggle with some things to get nearly as close to the optimum Input lag:
I usually play 2 games: Mainly CSGO and at the BlurBusters G-SYNC preview site (2014 <https://blurbusters.com/gsync/preview2/>) the best for input lag is ingame fps cap at 120 fps and G-SYNC/VSync enabled.
But at the Input Latency Master Sheet (<https://onedrive.live.com/view.aspx?cid ... 50hiq4wuf8>), the best for a 144Hz monitor, which I run, will be G-SYNC disabled and cap ingame fps_max 432 (3x144). Are these at general for all GSYNC Games or only SourceGames?
Second Game is CoD MW2 Warzone 2.0: i don't found any "valid" informations how Input lag differs on certain settings - at 2160p i get 90-100fps and at 1080p it will be +160fps - so what should I pick (nvcpl settings, ingame settings, ullm/reflex etc)?

I hope anyone can make it more clear for me

[jorimt]

Tl.dr to make it quick: what settings should i set for lowest possible Input Lag?

1. Lowest possible latency will always be G-SYNC off + V-SYNC off + framerate as high above the refresh rate without maxing GPU usage.
2. Lowest possible tear-free latency is G-SYNC on + V-SYNC on + framerate within the refresh rate + GPU usage below 99%.

What you ultimately use is down to situation and preference, sometimes on a per-game basis.

As for no-sync + uncapped vs. G-SYNC + capped, start by reading the below:
https://blurbusters.com/gsync/gsync101- ... ettings/9/

[SachsenPowl]

1. Lowest possible latency will always be G-SYNC off + V-SYNC off + framerate as high above the refresh rate without maxing GPU usage.
2. Lowest possible tear-free latency is G-SYNC on + V-SYNC on + framerate within the refresh rate + GPU usage below 99%.

ULLM Ultra, On, Off? What about Reflex?
For both scenarios. G-SYNC at 4K, 100fps looks really good compaired to a bit washed out 1080p. But it feels that >160 fps has a bigger advantage than the better look.

[jorimt]

ULLM Ultra, On, Off? What about Reflex?

All three reduce render queue latency, but only whenever the GPU usage is maxed (99%+). When it's not, they're effectively doing nothing to reduce latency further.

Reflex is superior to LLM On/Ultra and is considered their replacement. Use it in games that support it where GPU usage is maxed the majority of the time.

As for LLM On/Ultra, they don't work in DX12 or Vulkan, even when enabled, so can only be used in some DX11 and older titles, and there isn't always a guarantee they will do anything in those either. It's game/engine dependent in most cases.

Another way to reduce render queue latency in scenarios you can't use LLM or Reflex is to ensure your framerate cap is the limiting factor 99% of time while it is also preventing maxed GPU usage, which will result in render queue latency reduction similar to Reflex.

[SachsenPowl]

Thanks for the explanation.

I have a few other questions:
Does HDR add some kind of input lag?
How important is the refresh rate cap at x.0000 numbers (not 143.999 -> 144.0000)

[RealNC]

How important is the refresh rate cap at x.0000 numbers (not 143.999 -> 144.0000)

With VRR it doesn't matter.

[jorimt]

Does HDR add some kind of input lag?

Could depend on the monitor model (I.E. whether it has a G-SYNC module or not), but as far as I'm aware, usually little to none.

How important is the refresh rate cap at x.0000 numbers (not 143.999 -> 144.0000)

Similar to what @RealNC said, this rule does not apply to VRR, but only to low-lag standalone V-SYNC scenarios when limiting framerate with RTSS.

EDIT: just realized you meant rounding differences in physical refresh rate readouts, not decimal-level framerate limits. Either way, it still doesn't matter in majority of cases; I have a 240Hz monitor, and it shows as 239.97Hz in my OS, for instance.

[SachsenPowl]

Thank you.
On my previous Dell it was easy to "debloat" the EDID (software/driver) and get straight 144.000Hz
also it felt like a Day and Night difference if i loaded my delbloated profile.
On my 27GP950-B it makes no difference or i cannot feel it (non-GSYNC, fixed refresh).