New PS5/PS4 firmware releasing today. VRR (for HDMI 2.1 TVs and monitors) confirmed to arrive in "the coming months"

Tim42 · Mar 25, 2022

There are some things to be aware of in relation to VRR, LFC and the PS5 that could be problematic.

First of all, you should know that the PS5 currently only outputs a 120Hz signal if the setting is enabled in the system and a game explicitly enables it. Otherwise, the PS5 only uses a 60Hz signal.

As the PS5 has a HDMI 2.1 bandwidth limit of 32Gbps, a 120Hz mode at a UHD resolution means that a color subsampling of 4:2:2 is used plus a limited range signal - as opposed to an RGB/4:4:4 mode with the free choice of a full/limited range at 60Hz. This can lead to a slightly poorer color representation and, depending on the TV set, also to banding problems.

Furthermore, all screens have a limited VRR range, for example all LG OLED TVs have a VRR range of 40-120Hz. So if a source can't at least deliver a new frame every 25ms (40Hz) it has to use LFC (Low Framerate Compensation) for VRR to be effective, otherwise you'll end up with a tearing effect in case of varying framerates.
For LFC to work at all, however, it is necessary that the upper limit of the VRR range is at least 2.5x as large as the lower limit. I.e. LFC won't be active if your TV is getting a 60Hz signal because the VRR range would be 40-60Hz in this case.

So what does this mean for PS5 games and the upcoming VRR update?

If a game renders with less than 40FPS but the HDMI signal is 60Hz, then VRR cannot be active because it would require LFC to prevent screen tearing effects. The game or the system would have to switch to a 120Hz HDMI signal for LFC to become available, but this leads to the mentioned color subsampling / limited range signal.

If a game has a 60FPS target and the PS5 doesn't switch to a 120Hz signal, the effective VRR range will be 40-60Hz. Which will help compensate occasional drops below the target framerate down to 40FPS but doesn't help if the game could go beyond 60FPS. The latter would again require the PS5 to switch to a 120Hz signal.

So I hope everyone understands that it will be very important for Sony to output a 120Hz signal in VRR mode. Otherwise VRR will have little or no effect on most games.
At the same time, this will also mean that you have to live with the 4:2:2 colour sub-sampling in 120Hz mode.

In any case, game developers must additionally deliver patches that remove the upper framerate limit in order for a game to output more frames. I.e. the usual 30 or 60FPS cap has to be removed. Otherwise, the VRR update will again have little or no effect.

So I can only advise not to expect miracles from the update. In any case, we can only hope that Sony will deliver a proper VRR implementation after such a long time.

AnythingElse · Mar 26, 2022

I think this update screwed the 'game mode' setting on my TCL p605 tv. Now it just shows as "Not available" under Picture Settings...

Jokerman · Mar 26, 2022

Zelus said:
Now, I'll definitely admit that. Sony (in my opinion) has the best algorithm when it comes to picture quality. However, their software support is subpar from my personal experience. For example, my x900h looks terrible with VRR and I had a lot of crashes after the update. Maybe their new TVs are better from that standpoint but I had a bad enough experience to stay away from them for the near future.

There is no defence for Sony's handling of the x900h but their recent TVs are fine for software updates and of course now they have VRR.

Wideboyslim · Mar 26, 2022

Tim42 said:
There are some things to be aware of in relation to VRR, LFC and the PS5 that could be problematic.

First of all, you should know that the PS5 currently only outputs a 120Hz signal if the setting is enabled in the system and a game explicitly enables it. Otherwise, the PS5 only uses a 60Hz signal.

As the PS5 has a HDMI 2.1 bandwidth limit of 32Gbps, a 120Hz mode at a UHD resolution means that a color subsampling of 4:2:2 is used plus a limited range signal - as opposed to an RGB/4:4:4 mode with the free choice of a full/limited range at 60Hz. This can lead to a slightly poorer color representation and, depending on the TV set, also to banding problems.

Furthermore, all screens have a limited VRR range, for example all LG OLED TVs have a VRR range of 40-120Hz. So if a source can't at least deliver a new frame every 25ms (40Hz) it has to use LFC (Low Framerate Compensation) for VRR to be effective, otherwise you'll end up with a tearing effect in case of varying framerates.
For LFC to work at all, however, it is necessary that the upper limit of the VRR range is at least 2.5x as large as the lower limit. I.e. LFC won't be active if your TV is getting a 60Hz signal because the VRR range would be 40-60Hz in this case.

So what does this mean for PS5 games and the upcoming VRR update?

If a game renders with less than 40FPS but the HDMI signal is 60Hz, then VRR cannot be active because it would require LFC to prevent screen tearing effects. The game or the system would have to switch to a 120Hz HDMI signal for LFC to become available, but this leads to the mentioned color subsampling / limited range signal.

If a game has a 60FPS target and the PS5 doesn't switch to a 120Hz signal, the effective VRR range will be 40-60Hz. Which will help compensate occasional drops below the target framerate down to 40FPS but doesn't help if the game could go beyond 60FPS. The latter would again require the PS5 to switch to a 120Hz signal.

So I hope everyone understands that it will be very important for Sony to output a 120Hz signal in VRR mode. Otherwise VRR will have little or no effect on most games.
At the same time, this will also mean that you have to live with the 4:2:2 colour sub-sampling in 120Hz mode.

In any case, game developers must additionally deliver patches that remove the upper framerate limit in order for a game to output more frames. I.e. the usual 30 or 60FPS cap has to be removed. Otherwise, the VRR update will again have little or no effect.

So I can only advise not to expect miracles from the update. In any case, we can only hope that Sony will deliver a proper VRR implementation after such a long time.

The minimum range for VRR on LG Oleds goes as low as 20Hz if I read the table on rtings correctly: https://www.rtings.com/tv/tests/motion/variable-refresh-rate

jsnepo · Mar 26, 2022

Tim42 said:
There are some things to be aware of in relation to VRR, LFC and the PS5 that could be problematic.

First of all, you should know that the PS5 currently only outputs a 120Hz signal if the setting is enabled in the system and a game explicitly enables it. Otherwise, the PS5 only uses a 60Hz signal.

As the PS5 has a HDMI 2.1 bandwidth limit of 32Gbps, a 120Hz mode at a UHD resolution means that a color subsampling of 4:2:2 is used plus a limited range signal - as opposed to an RGB/4:4:4 mode with the free choice of a full/limited range at 60Hz. This can lead to a slightly poorer color representation and, depending on the TV set, also to banding problems.

Furthermore, all screens have a limited VRR range, for example all LG OLED TVs have a VRR range of 40-120Hz. So if a source can't at least deliver a new frame every 25ms (40Hz) it has to use LFC (Low Framerate Compensation) for VRR to be effective, otherwise you'll end up with a tearing effect in case of varying framerates.
For LFC to work at all, however, it is necessary that the upper limit of the VRR range is at least 2.5x as large as the lower limit. I.e. LFC won't be active if your TV is getting a 60Hz signal because the VRR range would be 40-60Hz in this case.

So what does this mean for PS5 games and the upcoming VRR update?

If a game renders with less than 40FPS but the HDMI signal is 60Hz, then VRR cannot be active because it would require LFC to prevent screen tearing effects. The game or the system would have to switch to a 120Hz HDMI signal for LFC to become available, but this leads to the mentioned color subsampling / limited range signal.

If a game has a 60FPS target and the PS5 doesn't switch to a 120Hz signal, the effective VRR range will be 40-60Hz. Which will help compensate occasional drops below the target framerate down to 40FPS but doesn't help if the game could go beyond 60FPS. The latter would again require the PS5 to switch to a 120Hz signal.

So I hope everyone understands that it will be very important for Sony to output a 120Hz signal in VRR mode. Otherwise VRR will have little or no effect on most games.
At the same time, this will also mean that you have to live with the 4:2:2 colour sub-sampling in 120Hz mode.

In any case, game developers must additionally deliver patches that remove the upper framerate limit in order for a game to output more frames. I.e. the usual 30 or 60FPS cap has to be removed. Otherwise, the VRR update will again have little or no effect.

So I can only advise not to expect miracles from the update. In any case, we can only hope that Sony will deliver a proper VRR implementation after such a long time.

Yeah. There is no way to force 120Hz on a PS5 unlike the Xbox. I have been trying to figure it to help lower the input latency but tl no avail. The game has to support 120Hz.

Hopefully the toggle for unsupported games means forced 120Hz.

2Blackcats · Mar 26, 2022

EvilBoris said:
They have funnily enough their implementation meant that games had no awareness of whether they were connected to a VRR display or not, so devs couldn't put options in only for those users.
This may have changed now.

Interesting

Theorry · Mar 26, 2022

Tim42 said:
There are some things to be aware of in relation to VRR, LFC and the PS5 that could be problematic.

First of all, you should know that the PS5 currently only outputs a 120Hz signal if the setting is enabled in the system and a game explicitly enables it. Otherwise, the PS5 only uses a 60Hz signal.

As the PS5 has a HDMI 2.1 bandwidth limit of 32Gbps, a 120Hz mode at a UHD resolution means that a color subsampling of 4:2:2 is used plus a limited range signal - as opposed to an RGB/4:4:4 mode with the free choice of a full/limited range at 60Hz. This can lead to a slightly poorer color representation and, depending on the TV set, also to banding problems.

Furthermore, all screens have a limited VRR range, for example all LG OLED TVs have a VRR range of 40-120Hz. So if a source can't at least deliver a new frame every 25ms (40Hz) it has to use LFC (Low Framerate Compensation) for VRR to be effective, otherwise you'll end up with a tearing effect in case of varying framerates.
For LFC to work at all, however, it is necessary that the upper limit of the VRR range is at least 2.5x as large as the lower limit. I.e. LFC won't be active if your TV is getting a 60Hz signal because the VRR range would be 40-60Hz in this case.

So what does this mean for PS5 games and the upcoming VRR update?

If a game renders with less than 40FPS but the HDMI signal is 60Hz, then VRR cannot be active because it would require LFC to prevent screen tearing effects. The game or the system would have to switch to a 120Hz HDMI signal for LFC to become available, but this leads to the mentioned color subsampling / limited range signal.

If a game has a 60FPS target and the PS5 doesn't switch to a 120Hz signal, the effective VRR range will be 40-60Hz. Which will help compensate occasional drops below the target framerate down to 40FPS but doesn't help if the game could go beyond 60FPS. The latter would again require the PS5 to switch to a 120Hz signal.

So I hope everyone understands that it will be very important for Sony to output a 120Hz signal in VRR mode. Otherwise VRR will have little or no effect on most games.
At the same time, this will also mean that you have to live with the 4:2:2 colour sub-sampling in 120Hz mode.

In any case, game developers must additionally deliver patches that remove the upper framerate limit in order for a game to output more frames. I.e. the usual 30 or 60FPS cap has to be removed. Otherwise, the VRR update will again have little or no effect.

So I can only advise not to expect miracles from the update. In any case, we can only hope that Sony will deliver a proper VRR implementation after such a long time.

VRR on Oleds can go as low as 20hz.
rest i agree. Reason i have 120 enabled all the the time on the series X in the options is to enable 120hz. You kinda can do that system wide.
This is not possible with PS5 indeed. Guess will see.

DieH@rd · Mar 26, 2022

Theorry said:
VRR on Oleds can go as low as 20hz.
rest i agree. Reason i have 120 enabled all the the time on the series X in the options is to enable 120hz. You kinda can do that system wide.
This is not possible with PS5 indeed. Guess will see.

C1 has the option to keep the panel refreshing at 120hz even if it detects that the incoming signal is 60hz. I keep it on all the time so I can get a reduced input latency on PS5 30/60fps games.

Theorry · Mar 26, 2022

DieH@rd said:
C1 has the option to keep the panel refreshing at 120hz even if it detects that the incoming signal is 60hz. I keep it on all the time so I can get a reduced input latency on PS5 30/60fps games.

Hmm CX doesnt have it?

Tora · Mar 26, 2022

The menu on the C1 is so much faster and smoother when you're playing 120hz content. Bit random but it's noticeable when I'm playing on ps5 where most content is 60hz Vs on Xbox where it's always refreshing at 120hz regardless of the title

DieH@rd said:
C1 has the option to keep the panel refreshing at 120hz even if it detects that the incoming signal is 60hz. I keep it on all the time so I can get a reduced input latency on PS5 30/60fps games.

There's no real drawback of doing this too. It reduces latency from 13ms to 10ms I believe

jsnepo · Mar 26, 2022

DieH@rd said:
C1 has the option to keep the panel refreshing at 120hz even if it detects that the incoming signal is 60hz. I keep it on all the time so I can get a reduced input latency on PS5 30/60fps games.

Really? How? Is it the boost thing?

DieH@rd · Mar 26, 2022

jsnepo said:
Really? How? Is it the boost thing?

Low Latency mode in Game Optimizer settings.

jsnepo · Mar 26, 2022

DieH@rd said:
Low Latency mode in Game Optimizer settings.

I've done that but when but when I check the VRR information display, it still says 60Hz fixed. Playing 120Hz games do show 120Hz fixed.

Tim42 · Mar 26, 2022

Wideboyslim said:
The minimum range for VRR on LG Oleds goes as low as 20Hz if I read the table on rtings correctly: https://www.rtings.com/tv/tests/motion/variable-refresh-rate

Theorry said:
VRR on Oleds can go as low as 20hz.

Unfortunately, this is not quite correct.
The information on rtings.com is somewhat misleading. I've already contacted them about it and they wanted to make it a bit clearer in the descriptions.

If you read through the test descriptions on rtings.com, you can see their test scenario.
What rtings.com does is apply a 120Hz (or whatever the max refresh rate of the monitor is) signal with a source that can handle LFC. Then they test down to which minimum frame rate the TV shows no abnormalities using LFC. They then list this value as the lower limit for VRR.

Anyone who understands how LFC works will immediately realise how nonsensical this indication in conjunction with VRR is. LFC is not a feature of the monitor, but a feature of the source. With LFC, the source retransmits a frame after the maximum hold time of the monitor (which it receives through the EDID).

LGD's OLEDs cannot hold a frame for longer than ~25ms, after which a refresh is compulsory, so the pixels must be driven again.
As I'm sure pretty much everyone is aware by now (the topic was in the press at the time), even with the maximum hold time of 25ms, there are problems that result in a flickering image due to the subpixels being powered for too long.

I.e. independent of this topic, it would be advantageous for LG OLEDs if the frame multiplication as done by LFC is not only performed when the maximum hold time is exceeded, but also at higher FPS outputs. I.e. if, for example, at a render speed of 40FPS (one image per 25ms), the source would instead send the same image every ~8.3ms (120Hz).

Btw. this is already partly the case with the XSX. With some titles, you can see how the effective refresh rate always fluctuates just below 120Hz, even though a game renders at a much slower speed.

MrBenchmark · Mar 26, 2022

Tim42 said:
Unfortunately, this is not quite correct.
The information on rtings.com is somewhat misleading. I've already contacted them about it and they wanted to make it a bit clearer in the descriptions.

If you read through the test descriptions on rtings.com, you can see their test scenario.
What rtings.com does is apply a 120Hz (or whatever the max refresh rate of the monitor is) signal with a source that can handle LFC. Then they test down to which minimum frame rate the TV shows no abnormalities using LFC. They then list this value as the lower limit for VRR.

Anyone who understands how LFC works will immediately realise how nonsensical this indication in conjunction with VRR is. LFC is not a feature of the monitor, but a feature of the source. With LFC, the source retransmits a frame after the maximum hold time of the monitor (which it receives through the EDID).

LGD's OLEDs cannot hold a frame for longer than ~25ms, after which a refresh is compulsory, so the pixels must be driven again.
As I'm sure pretty much everyone is aware by now (the topic was in the press at the time), even with the maximum hold time of 25ms, there are problems that result in a flickering image due to the subpixels being powered for too long.

I.e. independent of this topic, it would be advantageous for LG OLEDs if the frame multiplication as done by LFC is not only performed when the maximum hold time is exceeded, but also at higher FPS outputs. I.e. if, for example, at a render speed of 40FPS (one image per 25ms), the source would instead send the same image every ~8.3ms (120Hz).

Btw. this is already partly the case with the XSX. With some titles, you can see how the effective refresh rate always fluctuates just below 120Hz, even though a game renders at a much slower speed.

Thank you for this post.

Zones · Mar 27, 2022

Does anyone know how to disable ALLM on LG G1 / PS5?

I can select Game Optimiser myself if I want to, but as it stands, all other modes have multiple options and features disabled due to the forced ALLM on my TV, so any kind soul would happen to know how to disable ALLM via either the TV or the PS5?

xir · Mar 27, 2022

Huh ps5 is now triggering instant game response in my lg bx

delete · Mar 28, 2022

Zones said:
Does anyone know how to disable ALLM on LG G1 / PS5?

I can select Game Optimiser myself if I want to, but as it stands, all other modes have multiple options and features disabled due to the forced ALLM on my TV, so any kind soul would happen to know how to disable ALLM via either the TV or the PS5?

On your tv maybe turn off instant game response for the HDMI port used by your ps5?

delete · Mar 28, 2022

I'm enjoying the instant game response paired with the automatically switching from HDR to SDR. Makes using the streaming apps much better as I don't have to manually change the picture settings anymore.

delete · Mar 28, 2022

I wonder what DF mean at the below time stamp about LFC not solving the issue when games dip below 30 fps:

Edit: Perhaps it's in relation to improper frame pacing or if the cap isn't properly implemented, VRR may not smooth that out.

Gitaroo · Mar 28, 2022

delete said:
I wonder what DF mean at the below time stamp about LFC not solving the issue when games dip below 30 fps:

People claiming that helps xbsx for 30fps game. I tried it myself and see no difference. 30fps game still play like 30fps.

delete · Mar 28, 2022

Gitaroo said:
People claiming that helps xbsx for 30fps game. I tried it myself and see no difference. 30fps game still play like 30fps.

This is one of EvilBoris's tweets where he shows LFC working for a game that dips below 30fps. I'm so confused tbh, hopefully when this update comes out HDTV Test and DF can collab on a video explaining all of it.

I don't think anyone is claiming (at least I hope not) that LFC + VRR will make a game that is locked 30fps feel better. It should only make a difference if it can't hold a steady 30fps.

dieter can you explain the disparity between what EvilBoris has shown in his tweet and what John Linneman is claiming? You also had the impression that LFC does help in this week's DF Direct Weekly until John claimed it didn't.

Gitaroo · Mar 28, 2022

delete said:
This is one of EvilBoris's tweets where he shows LFC working for a game that dips below 30fps. I'm so confused tbh, hopefully when this update comes out HDTV Test and DF can collab on a video explaining all of it.

I don't think anyone is claiming (at least I hope not) that LFC + VRR will make a game that is locked 30fps feel better. It should only make a difference if it can't hold a steady 30fps.

Its artificial frame doubling when things dip below a certain threshold, frame dipping is still affecting input lag but image is less judder. Looks smoother but feel the same I gather.

delete · Mar 28, 2022

Gitaroo said:
Its artificial frame doubling when things dip below a certain threshold, frame dipping is still affecting input lag but image is less judder. Looks smoother but feel the same I gather.

Yeah that is exactly what LFC with VRR does except when the framerate isn't steady it does feel better. For a 30fps game at 60hz each new frame is displayed on the screen at 33ms, with frame doubling that means every frame rendered by the game is displayed twice on the display at 16.6ms intervals. If the framerate dips to 29 fps however, that that would require each new frame to be displayed on the screen 34.5ms, effectively this misses the 16.6ms frame doubling target of 60hz. Meaning that the next opportunity to display that new frame is 33 + 16.6ms = 49.6ms, which you would feel as input lag and stutter.

With VRR + LFC, because you don't have to target a static 60hz and can go as low as 40hz. You can get a frame doubling window for games that run between 20 - 30 fps (equates to 40hz and 60hz respectively). Meaning you don't have to wait an additional 16.6ms to display the next frame when the frame rate dips, just an additional 1.5ms that would be imperceivable.

k0fighter · Mar 28, 2022

I think I understand. So even with VRR it'll still be better feeling to play Elden Ring on XBOX Series X|S?

jsnepo · Mar 28, 2022

I noticed that in the base Xbox One (not S), VRR can be enabled for Xbox 360 games. Too bad 360 games have crushed blacks.

So how do we force the LG C1 to out in 120Hz again? I really like to do that with my PS5 to have lower input latency.

NightmaresHunter · Mar 28, 2022

Can someone fill a tech-dumb like me with what happening?

delete · Mar 29, 2022

k0fighter said:
I think I understand. So even with VRR it'll still be better feeling to play Elden Ring on XBOX Series X|S?

With VRR on PS5, and if Elden Ring supports VRR on PS5, it should feel the same as on Xbox Series X/S on a compatible display.

Until the firmware update is released we don't know how forcing VRR will affect elden ring on PS5. Also we don't know if From Software are going to patch in support for it.

NightmaresHunter said:
Can someone fill a tech-dumb like me with what happening?

PS5 go VRR

What TV do you have? I can tell you if you should care or not.

k0fighter · Mar 29, 2022

delete said:
With VRR on PS5, and if Elden Ring supports VRR on PS5, it should feel the same as on Xbox Series X/S on a compatible display.

So we shouldn't assume PS4 games running in back compat PS4 Pro mode won't just automatically work, it'll be a game by game basis?

Gitaroo · Mar 29, 2022

k0fighter said:
So we shouldn't assume PS4 games running in back compat PS4 Pro mode won't just automatically work, it'll be a game by game basis?

We dont even know if it works on bc games for sure.

delete said:
With VRR on PS5, and if Elden Ring supports VRR on PS5, it should feel the same as on Xbox Series X/S on a compatible display.

It should be better actually since ps5 version has a consistent 5-10fps lead in a lot of cases. Higher frame rate with VRR definitely feel better than lower frame rate with VRR.

delete · Mar 29, 2022

k0fighter said:
So we shouldn't assume PS4 games running in back compat PS4 Pro mode won't just automatically work, it'll be a game by game basis?

The blog post only mentions that VRR can only be applied to PS5 games. For PS5 games; if the game hasn't been patched to support it there is an option to force VRR anyway but that may cause issues.

We're also pleased to share that Variable Refresh Rate (VRR) is planned to release on PS5 in the coming months. On HDMI 2.1-compatible TVs and PC monitors, VRR dynamically syncs the refresh rate of the display to the PS5 console's graphical output. This enhances visual performance for PS5 games by minimizing or eliminating visual artifacts, such as frame pacing issues and screen tearing. Gameplay in many PS5 titles feels smoother as scenes render instantly, graphics look crisper, and input lag is reduced. Previously released PS5 games can be fully optimized for VRR through a game patch and future games may include VRR support at launch.

As an added option, you can also choose to apply VRR to PS5 games that don't support it. This feature may improve video quality for some games. If this results in any unexpected visual effects, you can turn off this option at any time. Both VRR and this secondary option can be turned on or off.

At this moment there is no indication that it will work for ps4 versions of games, even if they support the PS4 Pro.

k0fighter · Mar 29, 2022

delete said:
The blog post only mentions that VRR can only be applied to PS5 games. For PS5 games; if the game hasn't been patched to support it there is an option to force VRR anyway but that may cause issues.

At this moment there is no indication that it will work for ps4 versions of games, even if they support the PS4 Pro.

Oh shit, I'm thinking I need to play the PS4 version on PS5. I'm forgetting there's a native PS5 version. Sorry for the kind of dumb questions then.

delete · Mar 29, 2022

k0fighter said:
Oh shit, I'm thinking I need to play the PS4 version on PS5. I'm forgetting there's a native PS5 version. Sorry for the kind of dumb questions then.

Nah all good, shit is confusing.

NightmaresHunter · Mar 29, 2022

delete said:
PS5 go VRR

What TV do you have? I can tell you if you should care or not.

I've LG CX =]

delete · Mar 29, 2022

NightmaresHunter said:
I've LG CX =]

Then you should care about the vrr update as that will mean you will be able to finally fully utilise your LG CX for gaming.

What VRR does is changes the refresh rate (Hz) of the tv from anywhere between 40hz and 120hz to accommodate whatever frame rate the game is running at. The effect of this is smoother gaming in certain cases with more consistent input feel and timing.

thatJohann · Mar 29, 2022

Zones said:
Does anyone know how to disable ALLM on LG G1 / PS5?

I can select Game Optimiser myself if I want to, but as it stands, all other modes have multiple options and features disabled due to the forced ALLM on my TV, so any kind soul would happen to know how to disable ALLM via either the TV or the PS5?

Yeah I have an LG C1 OLED and can't find a setting anywhere on the C1 to turn on Instant Game Response - am I missing something? I just see Game Optimizer but can't find an extra setting for the Instant Game Response.

Edit: I see on a youtube video that if you are using HDMI ARC, it disables Instant Game Response? I'm using a sonos beam soundbar on HDMI ARC, maybe that's why Instant Game Response isn't there?

Tim42 · Mar 29, 2022

delete said:
With VRR + LFC, because you don't have to target a static 60hz and can go as low as 40hz. You can get a frame doubling window for games that run between 20 - 30 fps (equates to 40hz and 60hz respectively). Meaning you don't have to wait an additional 16.6ms to display the next frame when the frame rate dips, just an additional 1.5ms that would be imperceivable.

It's not quite that simple with LFC. As mentioned, LFC cannot work with a VRR range of 40-60 Hz.

For a brief overview of what LFC can do in which scenarios, I recommend these slides from AMD (#19 and 20 in particular).

To understand how VRR, VSync, and LFC work together, here's a simplified example - to keep things from getting too complicated, I've left out some technical details.
Let's assume we've got a monitor with a 60Hz signal (~16.7ms scanout) and a VRR min of 40Hz. The GPU has already rendered frame 1, i.e. it is ready to be sent to the monitor.
The game is rendering with ~30FPS but the rendering speed isn't quite stable.

So let's say the subsequent 3 frames are available as follows:

Frame 2 after 34.5ms (29FPS)
Frame 3 after 35.7ms (28FPS) - absolute time after frame 1 is 70.2ms
Frame 4 after 33.3ms (30FPS) - absolute time after frame 1 is 103.5ms

Scanout	Start Time	End Time	Visible Frame after Scanout
1	0	16.7	1
2	16.7	33.3	1
3	33.3	50.0	1 and 2 (Tearing)
4	50.0	66.6	2
5	66.6	83.3	2 and 3 (Tearing)
6	83.3	100.0	3
7	100.0	116.7	3 and 4 (Tearing)
8	116.7	133.3	4

As we can see, we will end up with a lot of tearing where pixels of multiple different frames are visible on the screen at the same time.

Scanout	Start Time	End Time	Visible Frame after Scanout
1	0	16.7	1
2	16.7	33.3	1
3	33.3	50.0	1
4	50.0	66.6	2
5	66.6	83.3	2
6	83.3	100.0	3
7	100.0	116.7	3
8	116.7	133.3	4

VSync eliminates all tearing but introduces stutter since frame 1 is visible for ~50ms while frame 2 and 3 are visible for ~33.3ms.

Scanout	Start Time	End Time	Visible Frame after Scanout
1	0	25.0	1
2	25.0	41.7	1
3	41.7	66.7	2
4	66.7	83.3	2
5	83.3	103.5	3
6	103.5	-	4

As we can see, we still end up with some stutter. Frame 1 and 2 are visible for ~41.7ms but Frame 3 is visible for ~20.2ms.

And finally, how it would look like with a 120Hz signal (~8.3ms scanout duration).

Scanout	Start Time	End Time	Visible Frame after Scanout
1	0	25.0	1
2	25.0	34.5	1
3	34.5	59.5	2
4	59.5	70.2	2
5	70.2	95.2	3
6	95.2	103.5	3
7	103.5	-	4

The situation is already a lot better with 120Hz. Frame 1 is visible for ~34.5ms, Frame 2 for ~35.7ms and Frame 3 for ~33.3ms.
But the image is not completely stutter-free even with this, if the frame rates fluctuate a bit more unfavorably.

This is where LFC comes in. With LFC, the GPU tries to insert additional frames over time in such a way that the moving image is as homogeneous as possible. This means that the duration in which the individual transmitted frames are visible is as equal as possible.

It should be clear to everyone that this does not always lead to a smooth motion experience, because LFC cannot perform miracles.

If someone wants to see how AMD implemented LFC in the GPU drivers, you can take a look at the code of the open source drivers for Linux.

Tim42 · Mar 29, 2022

delete said:
Then you should care about the vrr update as that will mean you will be able to finally fully utilise your LG CX for gaming.

This must be clearly limited to what I've described here.

Unless Sony automatically enables 120Hz mode for games with VRR, not a single 30FPS game will clearly benefit from VRR.
Without 120Hz, even with 60FPS games VRR will have extremely limited use.

However, if they enable a 120Hz output, then you will unfortunately have to live with a color subsampling of 4:2:2. This is not necessarily bad, since this limitation already existed with the PS4 Pro in UHD. But it is not optimal either and could lead to visualization problems in one or the other (older) game.

th1nk · Mar 29, 2022

Tim42 said:
It's not quite that simple with LFC. As mentioned, LFC cannot work with a VRR range of 40-60 Hz.

For a brief overview of what LFC can do in which scenarios, I recommend these slides from AMD (#19 and 20 in particular).

To understand how VRR, VSync, and LFC work together, here's a simplified example - to keep things from getting too complicated, I've left out some technical details.
Let's assume we've got a monitor with a 60Hz signal (~16.7ms scanout) and a VRR min of 40Hz. The GPU has already rendered frame 1, i.e. it is ready to be sent to the monitor.
The game is rendering with ~30FPS but the rendering speed isn't quite stable.

So let's say the subsequent 3 frames are available as follows:

Frame 2 after 34.5ms (29FPS)

Frame 3 after 35.7ms (28FPS) - absolute time after frame 1 is 70.2ms

Frame 4 after 33.3ms (30FPS) - absolute time after frame 1 is 103.5ms

Scanout Start Time End Time Visible Frame after Scanout
1 0 16.7 1
2 16.7 33.3 1
3 33.3 50.0 1 and 2 (Tearing)
4 50.0 66.6 2
5 66.6 83.3 2 and 3 (Tearing)
6 83.3 100.0 3
7 100.0 116.7 3 and 4 (Tearing)
8 116.7 133.3 4

As we can see, we will end up with a lot of tearing where pixels of multiple different frames are visible on the screen at the same time.

Scanout Start Time End Time Visible Frame after Scanout
1 0 16.7 1
2 16.7 33.3 1
3 33.3 50.0 1
4 50.0 66.6 2
5 66.6 83.3 2
6 83.3 100.0 3
7 100.0 116.7 3
8 116.7 133.3 4

VSync eliminates all tearing but introduces stutter since frame 1 is visible for ~50ms while frame 2 and 3 are visible for ~33.3ms.

Scanout Start Time End Time Visible Frame after Scanout
1 0 25.0 1
2 25.0 41.7 1
3 41.7 66.7 2
4 66.7 83.3 2
5 83.3 103.5 3
6 103.5 - 4

As we can see, we still end up with some stutter. Frame 1 and 2 are visible for ~41.7ms but Frame 3 is visible for ~20.2ms.

And finally, how it would look like with a 120Hz signal (~8.3ms scanout duration).

Scanout Start Time End Time Visible Frame after Scanout
1 0 25.0 1
2 25.0 34.5 1
3 34.5 59.5 2
4 59.5 70.2 2
5 70.2 95.2 3
6 95.2 103.5 3
7 103.5 - 4

The situation is already a lot better with 120Hz. Frame 1 is visible for ~34.5ms, Frame 2 for ~35.7ms and Frame 3 for ~33.3ms.
But the image is not completely stutter-free even with this, if the frame rates fluctuate a bit more unfavorably.

This is where LFC comes in. With LFC, the GPU tries to insert additional frames over time in such a way that the moving image is as homogeneous as possible. This means that the duration in which the individual transmitted frames are visible is as equal as possible.

It should be clear to everyone that this does not always lead to a smooth motion experience, because LFC cannot perform miracles.

If someone wants to see how AMD implemented LFC in the GPU drivers, you can take a look at the code of the open source drivers for Linux.

Thanks for taking the time to post this! 🙏

delete · Mar 29, 2022

Thanks Tim42 for that post, interesting to know that even with LFC there is some judder that can be experienced.

nihilence · Apr 16, 2022

Is this true that update breaks some tv options without work around?

Says they console forces allm which disables done features and there is no off switch. You have to do menu hunting on your tv to find solutions. Weird.

jsnepo · Apr 16, 2022

that bump :(

DC5remy · Apr 16, 2022

yikes. Just need an off switch

Senator Toadstool · Apr 16, 2022

How do I know if I have hdmi 2.1? i have vrr and my series x has vrr

DC5remy · Apr 16, 2022

Senator Toadstool said:
How do I know if I have hdmi 2.1? i have vrr and my series x has vrr

VRR only works on HDMI 2.1

AnythingElse · Apr 16, 2022

nihilence said:
Is this true that update breaks some tv options without work around?

Says they console forces allm which disables done features and there is no off switch. You have to do menu hunting on your tv to find solutions. Weird.

Yeah, I've been locked out of game mode on my TV for the PS5 since the update.

Kyle Cross · Apr 16, 2022

nihilence said:
Is this true that update breaks some tv options without work around?

Says they console forces allm which disables done features and there is no off switch. You have to do menu hunting on your tv to find solutions. Weird.

Yeah, Sony is forcing ALLM now so anything that adds latency is turned off.

nolifebr · Apr 16, 2022

DC5remy said:
VRR only works on HDMI 2.1

It works on 2.0 via AMD Free Sync (Xbox supports it, PS5 doesn't)

Teiresias · Apr 16, 2022

AnythingElse said:
Yeah, I've been locked out of game mode on my TV for the PS5 since the update.

Isn't the problem today it essentially locks you into the game mode? Luckily I can bypass all this on my C9, but it sucks the newer sets dinner let you do that.

Gestault · Apr 16, 2022

nihilence said:
Is this true that update breaks some tv options without work around?

Says they console forces allm which disables done features and there is no off switch. You have to do menu hunting on your tv to find solutions. Weird.

This is annoying to see, considering this would prevent the use of things like (among others) black frame insertion. This really does feel like "the worst of both worlds" w/ hands-on vs. hands-off, re: missing features the hardware can support, but still forcing elements that limit granular control.

New PS5/PS4 firmware releasing today. VRR (for HDMI 2.1 TVs and monitors) confirmed to arrive in "the coming months"

The Enlightened Wise Ones

nøthing but silence

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