120Hz reduces input lag of 30fps and 60fps!

[jorimt]

for example on this video he found that by cancelling VRR on PS5 Pro he gets significantly less input lag:

https://www.youtube.com/watch?v=Yzg69-yb_Sw

How could this be?

Unless I missed something while scrubbing through that video, he didn't perform any high speed testing and provided zero test numbers, so it may not be; he's just going by subjective feel, and it's not even a blind test (I.E. he know exactly which scenario is which, because he's the one toggling the settings) thus there's no way to objectively confirm anything.

[Enigma]

for example on this video he found that by cancelling VRR on PS5 Pro he gets significantly less input lag:

https://www.youtube.com/watch?v=Yzg69-yb_Sw

How could this be?

Unless I missed something while scrubbing through that video, he didn't perform any high speed testing and provided zero test numbers, so it may not be; he's just going by subjective feel, and it's not even a blind test (I.E. he know exactly which scenario is which, because he's the one toggling the settings) thus there's no way to objectively confirm anything.

He mentioned in the description:

LG C4 Latency:

4K 60hz 9.9ms
4K 60hz 6.8ms (boost)
4K 60hz 5.8ms (boost/no vrr)

4K 120hz 5.5ms
4K 120hz 2.4ms (boost)
4K 120hz 1.4ms (boost/no vrr)

PS5 Latency:

86ms 60hz (VRR on)
36ms 120hz (VRR off)
34ms 120hz (VRR off and HDR off)

HDCP turned OFF gives the gamer whilst in 120hz mode 4-6ms less depending on the game.

VRR on tv & console OFF lowers the latency from the PS5 latency pipeline by 20ms~ whilst in 120hz mode.

PS4 Enhance Button turned OFF lowers latency by 3-4ms

LG C4 in 120hz container runs the tv at 4.6ms with Boost Mode on.
*boost mode off gives the tv around 5.5ms~ input lag, 60hz with boost on is 9.4ms and 10.6ms without.

adding this to the image processing pipeline of the PS5s HDMI signal with server ping and controller bluetooth latency and you get around 84ms average in 60hz scenarios.At 120hz with these tricks you have around 38ms~ average on the entire pipeline instead, whice is A LOT faster!

[jorimt]

He mentioned in the description

Yes, but does he describe his test methodology and testing equipment in any of his videos? Because those numbers mean very little without that.

Further, VRR implementation is going to vary heavily per VRR-capable PS5 game...

Some VRR-capable PS5 titles support 60Hz, some 120Hz, some may be internally using VRR + V-SYNC, others VRR + V-SYNC off, etc.

And VRR performance can also vary on how high the average framerate in the given game can be sustained; for titles that are using VRR + V-SYNC and can sustain 120+ FPS at 120Hz, for instance, it will revert to standalone V-SYNC behavior, and VRR behavior will only engage whenever the framerate drops below the refresh rate.

[Enigma]

He mentioned in the description

Yes, but does he describe his test methodology and testing equipment in any of his videos? Because those numbers mean very little without that.

Further, VRR implementation is going to vary heavily per VRR-capable PS5 game...

Some VRR-capable PS5 titles support 60Hz, some 120Hz, some may be internally using VRR + V-SYNC, others VRR + V-SYNC off, etc.

And VRR performance can also vary on how high the average framerate in the given game can be sustained; for titles that are using VRR + V-SYNC and can sustain 120+ FPS at 120Hz, for instance, it will revert to standalone V-SYNC behavior, and VRR behavior will only engage whenever the framerate drops below the refresh rate.

So the games themselves have to implement VRR well? I thought the interaction is solely between the GPU (in the case of AMD FreeSync or HDMI Forum VRR) or the NVidia Gsync chip to the monitor itself. I initially assumed that interaction would add some input lag because of the extra hoops that you require the system to go through. Super thanks for all the explanations.

[jorimt]

So the games themselves have to implement VRR well?

Not all PS5 games are VRR capable, so the game determines 1) whether it will engage VRR behavior when that setting is enabled at the PS5 system-level, 2) what maximum physical refresh rate it supports and can run at (60Hz, 120Hz, etc), 3) whether the V-SYNC option is internally enabled at the game engine-level when VRR is, and 3) whether any in-game FPS limit is set below the refresh rate whenever VRR is engaged.

For #4, I have doubts any PS5 developer enforces a framerate limit slightly below the refresh rate to ensure VRR behavior remains engaged for games that the average framerate can otherwise exceed the refresh rate.

VRR on console is wild west territory; anything goes, and all the user has access to in this case is the VRR toggle on it and their TV.

As such, while we're faring much better latency-wise than we were in the ~2010s console era (where 150-500ms of input lag was not unheard of, due in part to laggy LCD/plasma TVs and game engines at the time), "fine tuning" the latency and/or the performance of a console is still a bit of an oxymoron.

[Chief Blur Buster]

So VRR doesn't change the display's inherent scanout Hz, but only changes the display's refreshing Hz? I thought the two were connected.

They become disconnected when VRR=ON.

Please remember Displays do not refresh all pixels simultaneously.

Cables and panels don't have infinite bandwidth, therefore they can only transmit (over cable) and refresh (onto panel) sequetially, like the letters of a book, or the days of a calendar, in a raster-fashion, top-to-bottom. See high speed videos of refresh cycles at www.blurbusters.com/scanout

60fps 60Hz = first pixel and last pixel refresh 1/60sec apart

60fps 60Hz at 144Hz-Max VRR = first pixel and last pixel refresh 1/144sec apart, even though frame rate and panel refresh rate is 60fps 60Hz

TL;DR: A higher-Hz will "paint" an individual refresh cycle faster onto the screen. Faster scanout = "I can paint the frame faster, with less latency between first pixel and last pixel refreshed, meaning all of the pixels are on the screen quicker, for your eyeballs to see".

Here's an example of 100fps=100Hz on a 144Hz(Max) VRR screen:


The refresh cycles are painted faster onto the panel (100fps 100Hz frames are scanned-out (aka painted) onto the screen in 1/144sec)