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[Corporal.Hicks]

I recently bought a 4K, 240 Hz QD-OLED monitor (Gigabyte FO32U2) and, although I'm pleased with its picture quality, the DSC technology is terrible. I never experienced any black screens on my old Gigabyte M27QP (1440p, 170 Hz) LCD monitor connected to my RTX4080S, but as soon as I connected the OLED monitor with DSC enabled, I started seeing them. The latest firmware update for my monitor has drastically reduced the frequency of black screens, so it's tolerable, but I still see them from time to time.

However, DSC affects my aiming very noticeably, and that is not tolerable. I have been playing Quake 1, 2 and 3 since 1999, so my aiming and reaction times are much better than the average gamer's. With DSC enabled, I can no longer aim accurately. I don't know if it's a lag issue or if the GPU drivers don't sync mouse movement correctly, but my precision takes a big hit with DSC enabled. Not even Vsync, or DLSS FG reduce my precision so much. Luckily my monitor has DSC switch and 1440p 240Hz is still very usable from up close on such big monitor (my monitor has dedicated 24'inch 1440p picture mode). Also, if I use HDMI 2.1 (48 Gbps), I can play at 4K 200 Hz 8-bit without DSC (or 170 Hz 10-bit), which is good enough for me (aiming feels perfect). However, if I had known that the DSC input lag was so noticeable, I would have bought the more expensive DP2.1 monitor and changed my GPU sooner.

Edit : Today, after a good night's sleep, I started testing everything again. Luckily, I found out why DSC affected my aim to such a noticeable degree. I changed the RGB range in my monitor's on-screen display (OSD) settings from 'manual' to 'Automatic', and the lag when aiming disappeared completely. It's a strange fix and I don't know why it works, but the difference is very noticeable.

To sum it up, 4K 240Hz with DSC works perfectly fine as long as RGB range in my monitor settings is set to automatic.

 

[Kuranghi]

DSC would not cause noticeable lag, when you flipped the Switch it probably performed a soft CEC reset which fixed your issues

 

[Corporal.Hicks]

DSC would not cause noticeable lag, when you flipped the Switch it probably performed a soft CEC reset which fixed your issues

Before buying OLED monitor, I read posts about DSC input lag. Some gamers noticed DSC input lag, but people like you tried to downplay the issue, thinking that the lag DSC lag is too low to be a real problem. However, after testing it myself, I can see that the gamers who talked about DSC input lag were absolutely correct.

However, I'm not 100% sure that lag is the problem. The problem may be caused by synchronisation with mouse movements. Even at 120 Hz without DSC, I get much better precision than at 240 Hz with DSC, and the input lag should be lower at 240 Hz with DSC.

It is what it is. I'm happy that gigabyte enginers thought about this problem and included DSC switch. No more black screens and 4K 200Hz 8 bit / 170Hz 10 bit is still good enough for me.

 

[Trogdor1123]

I'm not familiar with this but is it like black frame insertion?

 

[Corporal.Hicks]

I'm not familiar with this but is it like black frame insertion?

No, it's a totally different thing. Black screens caused by DSC are more like blue screens. The whole monitor loses the signal for 2–3 seconds (so you only see black screen), and this happens randomly, but usually when you change something in the game settings.

 

[DaciaJC]

I was under the impression DSC only caused black screens when you change from exclusive full-screen mode, such as when alt-tabbing -- is this not the case? I play pretty much every game in borderless windowed mode, so I can't say it ever bothered me much.

 

[Corporal.Hicks]

I was under the impression DSC only caused black screens when you change from exclusive full-screen mode, such as when alt-tabbing -- is this not the case? I play pretty much every game in borderless windowed mode, so I can't say it ever bothered me much.

I used to see them even when browsing the internet or working on the desktop, so it's definitely not an issue exclusive to full-screen mode. However, the latest firmware update for my monitor has significantly reduced this problem.

 

[Kuranghi]

DSC does not inherently add any meaningful input lag (microseconds), but crap implementations of it do, this is the problem.

Your thread is FUD, my source is Blur Busters.

 

[Corporal.Hicks]

DSC does not inherently add any meaningful input lag (microseconds), but crap implementations of it do, this is the problem.

Your thread is FUD, my source is Blur Busters.

It's funny you mentioned the Blur Busters forum, because this is where I read negative comments about DSC input lag, and I should trust these people instead of ignoring what they said. You don't notice the DSC input lag, so good for you, but for me it's definitely a problem.

 

[Kuranghi]

It's funny you mentioned the Blur Busters forum, because this is where I read negative comments about DSC input lag, and I should trust these people instead of ignoring what they said. You don't notice the DSC input lag, so good for you, but for me it's definitely a problem.

Its the first result on Google:

 

[ItsGreat]

Thirsty young man?

 

[JohnnyFootball]

DSC is an amazing piece of technology. It used to cause minor issues on nvidia GPUs such as the alt-tab, but in my experience that has been completely solved on my 4090 240Hz QD-OLED setup.

There have been numerous tests comparing DSC and non-DSC settings and there has been no difference in visual quality or performance.

DSC is also the future as it is going to be more and more challenging to push the bandwidth needed to get over 240 fps at 4K.

Plus, you are going to need a mega high quality cable to push full 80 Gbps bandwidth through true DP2.1.

 

[Corporal.Hicks]

Its the first result on Google:

That quote is false because DSC input lag can be measured.

However, the general consensus is that this small amount is imperceptible and I believed it. However, having tested this technology myself, I know that DSC affects my aiming. I'm not sure if that's just a matter of lag, because such an extremely small amount of lag shouldn't be noticeable. However, the mouse movement is clearly not synchronised with the picture as it should be, because it feels stiff.

Not everyone is equally sensitive to input lag or stuttering. While most people can't see microstutters (even in the TES Oblivion remaster), others can. Just because you didn't experience the problem with DSC personally doesn't mean that others can't.

People on the Blurbusters forum have noticed this problem with different monitors, so even if we assume that certain monitors are to blame (because of an implementation issue like you trying to suggest), there's no way of knowing which models are affected, so it's like a lottery. These OLED monitors aren't that cheap, and do you really want people to risk their hard-earned money and play a lottery?

 

[Garibaldi]

I switched it off on my 4K OLED monitor as it was doing the occasional black frame drop outs when I had the refresh over 120. Annoying crap.

 

[Corporal.Hicks]

DSC is an amazing piece of technology. It used to cause minor issues on nvidia GPUs such as the alt-tab, but in my experience that has been completely solved on my 4090 240Hz QD-OLED setup.

There have been numerous tests comparing DSC and non-DSC settings and there has been no difference in visual quality or performance.

DSC is also the future as it is going to be more and more challenging to push the bandwidth needed to get over 240 fps at 4K.

Plus, you are going to need a mega high quality cable to push full 80 Gbps bandwidth through true DP2.1.

I havent noticed issued when alt-tabing from full screen games.

However, DSC is not lossless. I have noticed small artefacts on grey gradients, such as horizontal lines that look almost like burn-in. However, as soon as you disable DSC, they disappear immediately.

DP2.1 cables are very short, but I have seen a couple of expensive 1.2 m ones on the DisplayPort certification list, so it's not a problem that would bother me more than black screens, or problems when aiming in FPS games.

Edit - I did some more testing today and it seems that G-Sync introduces lag when DSC is enabled. When I turned off G-Sync, games with DSC were definitely way more responsive (mouse no longer felt that stiff). However, I don't want to play without G-Sync, and the thing is, G-Sync without DSC works perfectly (without any lag).

 

[Kuranghi]

That quote is false because DSC input lag can be measured.

However, the general consensus is that this small amount is imperceptible and I believed it. However, having tested this technology myself, I know that DSC affects my aiming. I'm not sure if that's just a matter of lag, because such an extremely small amount of lag shouldn't be noticeable. However, the mouse movement is clearly not synchronised with the picture as it should be, because it feels stiff.

Not everyone is equally sensitive to input lag or stuttering. While most people can't see microstutters (even in the TES Oblivion remaster), others can. Just because you didn't experience the problem with DSC personally doesn't mean that others can't.

People on the Blurbusters forum have noticed this problem with different monitors, so even if we assume that certain monitors are to blame (because of an implementation issue like you trying to suggest), there's no way of knowing which models are affected, so it's like a lottery. These OLED monitors aren't that cheap, and do you really want people to risk their hard-earned money and play a lottery?

What refresh rate are you generally running your monitor at? 60hz? Or are you trying to hit 240hz whenever you can?

Please stop making these side comments about 'some people cant detect lag like me' and 'people dont notice microstutters', you do not know me and none of these posts i have made have been about whether you can notice lag or whatever.

My posts are to highlight that your title is FUD and wrong and the problem is your specific monitor's implementation of DSC, or some other part of your HW chain.

Thats all I'm pointing out, I myself hate lag and microstutters and I very much can notice it/them even when its something 99.9% of others would never care about.

Also, those input lag readings on rtings are within a margin of error, they record multiple times and take an average, those differences could've been purely because the input lag measuring method was slightly differently aligned the 2nd time.

The fact that there's absolutely no difference in the 60hz numbers indicates this since even 4K@240hz fits within the bandwidth of the DP 2.1 connection on your monitor without DSC.

Which also begs the question: Why are you even enabling DSC?

 

[IFireflyl]

Pervert.

 

[Corporal.Hicks]

What refresh rate are you generally running your monitor at? 60hz? Or are you trying to hit 240hz whenever you can?

Please stop making these side comments about 'some people cant detect lag like me' and 'people dont notice microstutters', you do not know me and none of these posts i have made have been about whether you can notice lag or whatever.

My posts are to highlight that your title is FUD and wrong and the problem is your specific monitor's implementation of DSC, or some other part of your HW chain.

Thats all I'm pointing out, I myself hate lag and microstutters and I very much can notice it/them even when its something 99.9% of others would never care about.

Also, those input lag readings on rtings are within a margin of error, they record multiple times and take an average, those differences could've been purely because the input lag measuring method was slightly differently aligned the 2nd time.

The fact that there's absolutely no difference in the 60hz numbers indicates this since even 4K@240hz fits within the bandwidth of the DP 2.1 connection on your monitor without DSC.

Which also begs the question: Why are you even enabling DSC?

I played Quake 2 at 4K with a 240 Hz refresh rate and a 237 fps lock (G-Sync) and few other games where I can hit 240fps all the time. I feel the lag on the desktop as well (my desktop is set to 4K resolution and 240Hz), not just when playing games. All these problems go away immediately without DSC, but then I'm limited to 1440p 240Hz (instead of 4K 240Hz).

I can enjoy playing games at 4K 240Hz with DSC enabled on my monitor, but I have to turn off G-sync. For some strange reason DSC feels way more responsive without g-sync. However, I don't want to play without G-Sync, and G-Sync without DSC works perfectly (without any lag).

All these gamers who have noticed DSC problems have heard the same excuse from people that tried to downplay their honest observations: "That's your specific monitor for blame". People noticed this input latency problem on MSI, Asus, Dell, and now Gigabyte (my monitor), so at this point I rather believe it's an issue with DSC itself rather than specific model.

 

[Kuranghi]

I played Quake 2 at 4K with a 240 Hz refresh rate and a 237 fps lock (G-Sync) and few other games where I can hit 240fps all the time. I feel the lag on the desktop as well (my desktop is set to 4K resolution and 240Hz), not just when playing games. All these problems go away immediately without DSC, but then I'm limited to 1440p 240Hz (instead of 4K 240Hz).

I can enjoy playing games at 4K 240Hz with DSC enabled on my monitor, but I have to turn off G-sync. For some strange reason DSC feels way more responsive without g-sync. However, I don't want to play without G-Sync, and G-Sync without DSC works perfectly (without any lag).

All these gamers who have noticed DSC problems have heard the same excuse from people that tried to downplay their honest observations: "That's your specific monitor for blame". People noticed this input latency problem on MSI, Asus, Dell, and now Gigabyte (my monitor), so at this point I rather believe it's an issue with DSC itself rather than specific model.

Why do you get limited to 1440p@240hz? Because you're using HDMI?

 

[Corporal.Hicks]

Why do you get limited to 1440p@240hz? Because you're using HDMI?

If I want to use 240Hz refresh rate my resolution is limited to 1440p on both DP1.4 and HDMI 2.1 inputs. I can achieve up to 4K at 200 Hz with an HDMI connection, which would be good enough for me. However, for some strange reason, I get black screens when G-Sync is enabled on the HDMI input. G-Sync works stable on my monitor, but only when using DisplayPort.

 

[Kuranghi]

If I want to use 240Hz refresh rate my resolution is limited to 1440p on both DP1.4 and HDMI 2.1 inputs. I can achieve up to 4K at 200 Hz with an HDMI connection, which would be good enough for me. However, for some strange reason, I get black screens when G-Sync is enabled on the HDMI input. G-Sync works stable on my monitor, but only when using DisplayPort.

Have you tried different HDMI cables? Ime often even cables that claim to be "Ultra High-Speed Certified" are lying, you need one where when you scan the QR code it goes to the HDMI Alliance website and says its 100% certified.

I would also try taking the cable out and cleaning the heads of both ends with distilled water. I have experience of simple things like that fixing black screen on HDMI 2.1 inputs on displays.

Also removing and replugging cables can sort of reset the connection between the output device (GPU in this case) and the display, fixing black screens and other weird behaviour. HDMI is just finicky sometimes because of CEC and the like.

 

[Corporal.Hicks]

Have you tried different HDMI cables? Ime often even cables that claim to be "Ultra High-Speed Certified" are lying, you need one where when you scan the QR code it goes to the HDMI Alliance website and says its 100% certified.

I would also try taking the cable out and cleaning the heads of both ends with distilled water. I have experience of simple things like that fixing black screen on HDMI 2.1 inputs on displays.

Also removing and replugging cables can sort of reset the connection between the output device (GPU in this case) and the display, fixing black screens and other weird behaviour. HDMI is just finicky sometimes because of CEC and the like.

I'm using the cables that came with my monitor. The HDMI connection works perfectly stable without G-Sync, but as soon as I enable G-Sync, black screens start appearing frequently (regardless of resolution or Hz; even at 1440p and 60 Hz). I suspect it's a bug in either the monitor firmware or the Nvidia drivers.

Edit: I changed the HDMI port, but I'm still using the same cable. Now, I'm no longer seeing black screens even with Gsync

 

[Celcius]

I refuse to upgrade to a newer monitor before I upgrade to a 50 series card. DSC is the reason why. I want full native bandwidth.

 

[phant0m]

Bro if you can 'feel' a 0.4ms difference then I've got a bridge to sell you

 

[Tarin02543]

It's because you are running 4K through DP 1.4, you need 2.1 HDMI to get good enough bandwidth for DSC not to cause trouble. I use hdmi on my 360 hz qd oled

 

[Kuranghi]

I'm using the cables that came with my monitor. The HDMI connection works perfectly stable without G-Sync, but as soon as I enable G-Sync, black screens start appearing frequently (regardless of resolution or Hz; even at 1440p and 60 Hz). I suspect it's a bug in either the monitor firmware or the Nvidia drivers.

Edit: I changed the HDMI port, but I'm still using the same cable. Now, I'm no longer seeing black screens even with Gsync

I had assumed your GPU supported DP 2.1, but its 1.4a, now I understand why DSC is necessary and using the HDMI 2.1 port will allow for less DSC to be applied to the signal.

Checking rtings I see that there aren't many DP 2.1 monitors and most of them are from this and last year. I guess a lot of ultra high refresh rate (240hz) displays are 1440p rather than 4K so they didnt consider it that important to put those newer port types on them when most recent high-end GPUs have an HDMI 2.1 port.

Anyway, I'm glad that its seemingly fixed. This means you can play at 1440p@240hz with G-Sync and without DSC iirc?

 

[Corporal.Hicks]

I had assumed your GPU supported DP 2.1, but its 1.4a, now I understand why DSC is necessary and using the HDMI 2.1 port will allow for less DSC to be applied to the signal.

Checking rtings I see that there aren't many DP 2.1 monitors and most of them are from this and last year. I guess a lot of ultra high refresh rate (240hz) displays are 1440p rather than 4K so they didnt consider it that important to put those newer port types on them when most recent high-end GPUs have an HDMI 2.1 port.

Anyway, I'm glad that its seemingly fixed. This means you can play at 1440p@240hz with G-Sync and without DSC iirc?

Yes, I can play at 1440p 240Hz without DSC, and with Gsync enabled. For some strange reasons using 2'nd HDMI port fixed black screens and connection is perfectly stable. I also feel that HDMI connection reduced that stiff mouse movement that bothered me with DSC enabled (maybe because HDMI has higher bandwidth and DSC compression is less agressive), not to mention I also noticed improvement when I changed GPU scaling to monitor scaling in the drivers (without DSC this settings has no perceptable impact on my aim, but with DSC it has). Now aiming even at 4K 240Hz with DSC feels responsive.

I'm happy now, but I would still recommend that people spend the extra money on a DP2.1 monitor. That would solve all these problems. Without DSC, I never experienced a black screen and my aim always felt responsive, regardless of the Nvidia driver settings.

 

[Kuranghi]

Yes, I can play at 1440p 240Hz without DSC, and with Gsync enabled. For some strange reasons using 2'nd HDMI port fixed black screens and connection is perfectly stable. I also feel that HDMI connection reduced that stiff mouse movement that bothered me with DSC enabled (maybe because HDMI has higher bandwidth and DSC compression is less agressive), not to mention I also noticed improvement when I changed GPU scaling to monitor scaling in the drivers (without DSC this settings has no perceptable impact on my aim, but with DSC it has). Now aiming even at 4K 240Hz with DSC feels responsive.

I'm happy now, but I would still recommend that people spend the extra money on a DP2.1 monitor. That would solve all these problems. Without DSC, I never experienced a black screen and my aim always felt responsive, regardless of the Nvidia driver settings.

So without changing scaling to monitor from GPU you still feel the lag even using this 2nd HDMI port? I would try changing back to the 1st port now and then you'll know if it was just a weird HDMI cable signalling issue that caused the black screens and if thats fixed then test the scaling on both settings, then atp you'd know if it was that the whole time.

Maybe the monitor scaling is a bit slower but it lined up better with the GPUs DSC lag compensation value.

 

[coolmast3r]

What's even more frustrating is that many monitor manufacturers still refuse to put proper DP 2.1 UHBR20 (so full 80gbps bandwidth) on premium grade monitors. A $1000 monitor capable of 4K 240HZ + 1080p 480HZ (dual mode) should not come with DP 1.4 in 2025. Like, you've gone this far and have made a top of the line monitor only to bottleneck it by giving it a subpar connectivity options and still ask a premium price for it...

 

[Corporal.Hicks]

So without changing scaling to monitor from GPU you still feel the lag even using this 2nd HDMI port? I would try changing back to the 1st port now and then you'll know if it was just a weird HDMI cable signalling issue that caused the black screens and if thats fixed then test the scaling on both settings, then atp you'd know if it was that the whole time.

Maybe the monitor scaling is a bit slower but it lined up better with the GPUs DSC lag compensation value.

Today, after a good night's sleep, I started testing everything again. Luckily, I found out why DSC affected my aim to such a noticeable degree. It was as if I were playing with motion interpolation on a TV, or when using crappy Lossless Scaling FG (I could feel the lack of precision during fast mouse movement). I changed the RGB range in my monitor's on-screen display (OSD) settings from 'manual' to 'Automatic', and the lag when aiming disappeared completely. It's a strange fix and I don't know why it works, but the difference is very noticeable.

To sum it up, 4K 240Hz with DSC works perfectly fine as long as RGB range in my monitor settings is set to automatic.

Regarding GPU vs. monitor scaling, I discovered that using monitor scaling deactivated VRR at lower resolutions when using HDMI, which explains the difference I could feel when aiming with these two scaling options. VRR only works over HDMI on my monitor at 4K; at any lower resolution, G-Sync deactivates. This is not the case with DP1.4, because G-Sync works no matter what resolution is chosen.

 

[kizito]

Today, after a good night's sleep, I started testing everything again. Luckily, I found out why DSC affected my aim to such a noticeable degree. It was as if I were playing with motion interpolation on a TV, or when using crappy Lossless Scaling FG (I could feel the lack of precision during fast mouse movement). I changed the RGB range in my monitor's on-screen display (OSD) settings from 'manual' to 'Automatic', and the lag when aiming disappeared completely. It's a strange fix and I don't know why it works, but the difference is very noticeable.

To sum it up, 4K 240Hz with DSC works perfectly fine as long as RGB range in my monitor settings is set to automatic.

Regarding GPU vs. monitor scaling, I discovered that using monitor scaling deactivated VRR at lower resolutions when using HDMI, which explains the difference I could feel when aiming with these two scaling options. VRR only works over HDMI on my monitor at 4K; at any lower resolution, G-Sync deactivates. This is not the case with DP1.4, because G-Sync works no matter what resolution is chosen.

Can you edit the title of the thread then ?
I have been playing with DSC on a 4k 240hz monitor and am very sensitive to input lag. Never felt any difference and reports show a difference of 0.4 ms which is impossible to notice.

 

[Corporal.Hicks]

Can you edit the title of the thread then ?
I have been playing with DSC on a 4k 240hz monitor and am very sensitive to input lag. Never felt any difference and reports show a difference of 0.4 ms which is impossible to notice.

I can't, but perhaps the moderator EviLore could change the thread name slightly.

I will also add my final observations:
-HDMI 2.1 with DSC doesnt affect my aiming in any perceptable way if monitor settings are set correctly (RGB range automatic)
-DP1.4 still has some lag with DSC, but it's reduced a lot with correct settings (RGB range automatic). I'm guessing it has something to do with DSC compression, after all DP1.4 has way lower bandwidth compared to HDMI 2.1.
- Kuranghi The suggestion to check the HDMI cable/port was very helpful. I would never have thought that a HDMI port on a new monitor could be causing troubles, but it seems that's the case. The HDMI port 2 connection is perfectly stable, while the HDMI port 1 has a black screens.

And for impressions of OLED technology itself:
-The contrast difference between IPS LCD and OLED is huge, and I feel likie on OLED the picture quality has no weak points (there's nothing that annoyed me, not even VRR flickering). I was afraid that the current QD-OLEDs are too dim (because so many youtubers complained about it), but I was wrong. Even in SDR, an extremely dim Sony Megatron shader mask is usable, whereas on my previous 400-nit LCD it wasn't. That's how bright my current QD-OLED is!
-For me, having a 4K monitor is great because I use CRT shader masks for retro games, and also photos look a little bit better. However, I feel like the difference compared to my previous 1440p monitor isnt that big. The difference between 4K and 1440p it's not that obvious unless you are looking at monitor at 60cm distance. I wouldn't mind using a 1440p monitor for most tasks. Also, I feel that a 27-inch monitor is more practical for gaming at close range.