NVIDIA G-Sync Pulsar monitor - Asus ROG Strix XG27AQNGV

[kyube]

What's broken with the Pulse Width slider in the higher refresh rates? Seems to act the same way to me 10-100 adjustment and reduces brightness in the same way the 60hz mode does.

viewtopic.php?t=15149&start=580#p123478
According to your anecdote here, this should never be the case if the allowed duty cycle range is identical between all refresh rate modes.
360Hz @ 10% duty cycle → 2,7778 ms * 0,1 = 0,27778 ms strobe 'on' period; 1000 / 0,27778 = ~3600 Hz “effective refresh rate”
60Hz @ 10% duty cyle → 16,6667 ms * 0,1 = 1,6667 ms strobe 'on' period; 1000 / 1,6667 = ~600 Hz "effective refresh rate"

As you can see, 360Hz should scale much faster to better clarities than 60Hz, which isn't the case in practice.
For 60Hz to be crystal clear at 2880 px/s (Hz), you'd need to have a strobe 'On' period of of 0,34722 ms
That requires a 2,08333333291667 % duty cycle @ 60Hz.
As per anecdotal data from here, at ~1700 cd/m² voltage boosting, that's ~35 cd/m²

My claim is that 360Hz only has a "allowable" duty cycle range of, at best, x–25% PW
60Hz can get to x–2% PW.

Sadly, TFTCentral hasn't given a strobe on & off period table for the QHD@360Hz Pulsar models, which he did for his previous KTC M27P6 review...

[Argus]

I have the acer model and I rolled back to the initial firmware. Could it have something to do with me using a 40 series gpu instead of a 50?

Yes, single head limit of the DP1.4 port on 20/30/40 series cards.

NVIDIA and DSC - ToastyX Wrote:
NVIDIA's driver currently ignores EDID overrides if Display Stream Compression (DSC) is active and the maximum resolution @ refresh rate combination exceeds the GPU's single-head pixel clock limit:

GTX 1600-series: 1330 MHz
RTX 2000-series: 1330 MHz
RTX 3000-series: 1335 MHz
RTX 4000-series: 1350 MHz
RTX 5000-series: Not affected

Workarounds:

SRE can add custom GPU-scaled resolutions but not custom refresh rates: https://www.monitortests.com/forum/Threa...Editor-SRE
Use RegEdit to disable using multiple heads, but the pixel clock will be limited to the single-head limit:
Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\#### (usually 0000)
Value: "EnableTiledDisplay"=dword:00000000

That's unfortunate.
Is there no way to disable DSC on the Acer model for now?

[liquidshadowfox]

I rolled back the firmware today to confirm this problem goes away, 90-360hz is clean. Current firmware even a 1 FPS adjustment up or down causes ghosting between 90-180 FPS which negatively effects the clarity.

This is amazing! Thanks for that. Hopefully this will be adressed soon... Now having clear proof etc.

Some good news, Nvidia were able to recreate the issue and are working on a fix I have been told

who told you? excited that this monitor will get another firmware update to fix pulsar. Any word on release date? I assume it might take them another 3 months before we see the update.

[kyube]

That's unfortunate.
Is there no way to disable DSC on the Acer model for now?

Your only option would be to wait for Nvidia to release 2nd firmware update, to reap the benefits of the higher BW HDMI port and the fixed VRR+strobing implementation (which, according to brownvim, is planned to happen at some point in the future)
You could technically 'disable DSC' by running QHD@240Hz through DP1.4.
That's within the limits of DP1.4, as per this calculator

1. Does the new firmware update allow for full bandwith via HDMI 2.1, i.e. no DSC? I guess bandwidth limitations would still make only 240 Hz viable with no DSC, but that is more than enough. If not, is the firmware update worth it anyway, if I am not interested in the new fixed 60 Hz mode?

The HDMI 2.1 port is FRL5, according to TFTCentral, which isn't enough to drive QHD@360Hz
DP1.4 and the FRL5 port are able to achieve QHD@240Hz though. I don't know whether the latter port would work with Pulsar and/or ULMB2

2. I generally had the experience the newer the NVidia drivers after 572.83 the worse. What is the oldest driver fully compatible with the pulsar technology, and does it differ between the original and the new firmware?

I'd start with January 7 2026 as a cut-off date up to today.
This limits you to 591.74, 591.86, 595.59, 595.71, 595.79

3. In the control panel, is it better to set the scaling by GPU or by the monitor? I never had a monitor with a dedicated GSync chip before, so I standardly use GPU scaling, is there any difference here?

I'd stick to GPU scaling.

4. What is the best framecapping method to use with this monitor? Right now, I am using Special K and the Latent Sync limiter (no VSync, tearing ON) with the 1/2 refresh rate option (so approx 179.99 FPS) in most games; with the 1/3 refresh rate option (so approx 120 FPS) in the games that struggle to get above stable 130 FPS in QHD (such as Hell is Us).

SpecialK is one of the best external frame rate limiter solutions on the market.
SK's Latent Sync is likely redundant, as you're using VRR+Strobing (Pulsar) already to combat tearing.
It depends what you mean with "best":
- Best for total system latency? SK (with Reflex injected, to lower the depth of the render-ahead queue)
- Best for tearing management in VRR use? Not necessary
- Best for 'smoothness' (pacing)? SK

[brownvim]

I rolled back the firmware today to confirm this problem goes away, 90-360hz is clean. Current firmware even a 1 FPS adjustment up or down causes ghosting between 90-180 FPS which negatively effects the clarity.

This is amazing! Thanks for that. Hopefully this will be adressed soon... Now having clear proof etc.

Some good news, Nvidia were able to recreate the issue and are working on a fix I have been told

who told you? excited that this monitor will get another firmware update to fix pulsar. Any word on release date? I assume it might take them another 3 months before we see the update.

A guy on Overclockers Forums, I think he works for TFTCentral, has direct contact with Nvidia Pulsar developers.

No idea when it will be fixed, i'm just glad we got a response.

He mentioned Nvidia Pulsar devs actively check the BlurBusters Forums so I think they will be aware of all the issues and Kyubes moaning

[brownvim]

Hello, I also have this monitor.

I had a little trouble getting it working, as with me using the 572.83 driver on a 5090 there were random black screens in games when connected via DP 1.4 (and HDMI 2.1 was limited to 120 Hz), so I updated to the 591.86 driver and everything seems to be working fine now, 360 Hz 10 bit depth HDR when connected by DP 1.4 (still using the original firmware it came with). But I still have few questions which hopefully someone of you will know answer for:

1. does the new firmware update allow for full bandwith via HDMI 2.1, i.e. no DSC? I guess bandwidth limitations would still make only 240 Hz viable with no DSC, but that is more than enough. If not, is the firmware update worth it anyway, if I am not interested in the new fixed 60 Hz mode?

2. I generally had the experience the newer the NVidia drivers after 572.83 the worse. What is the oldest driver fully compatible with the pulsar technology, and does it differ between the original and the new firmware?

3. In the control panel, is it better to set the scaling by GPU or by the monitor? I never had a monitor with a dedicated GSync chip before, so I standardly use GPU scaling, is there any difference here?

4. What is the best framecapping method to use with this monitor? Right now, I am using Special K and the Latent Sync limiter (no VSync, tearing ON) with the 1/2 refresh rate option (so approx 179.99 FPS) in most games; with the 1/3 refresh rate option (so approx 120 FPS) in the games that struggle to get above stable 130 FPS in QHD (such as Hell is Us).

I have updated to the latest Nvidia Drivers 595.79, the previous ones had issues but its been fine now.

Stay on the older Pulsar firmware if you are not interested in the 60hz mode, its only worth it if your games are going to be above 180fps, anything below has introduced ghosting in the newer firmware. Which is in the process of being fixed.

[Argus]

That's unfortunate.
Is there no way to disable DSC on the Acer model for now?

Your only option would be to wait for Nvidia to release 2nd firmware update, to reap the benefits of the higher BW HDMI port and the fixed VRR+strobing implementation (which, according to brownvim, is planned to happen at some point in the future)
You could technically 'disable DSC' by running QHD@240Hz through DP1.4.
That's within the limits of DP1.4, as per this calculator

SpecialK is one of the best external frame rate limiter solutions on the market.
SK's Latent Sync is likely redundant, as you're using VRR+Strobing (Pulsar) already to combat tearing.
It depends what you mean with "best":
- Best for total system latency? SK (with Reflex injected, to lower the depth of the render-ahead queue)
- Best for tearing management in VRR use? Not necessary
- Best for 'smoothness' (pacing)? SK

So I'd need to downgrade my cable to disable DSC? I'm currently running a 2.1 DP and am able to select higher than QHD@240Hz.

Piggybacking on the SK question cuz I'm interested in the smoothness and frame pacing aspect of SK. Is there a specific config I need to setup to best frame pacing? Thanks.

[kyube]

So I'd need to downgrade my cable to disable DSC? I'm currently running a 2.1 DP and am able to select higher than QHD@240Hz.

No, you only need to set your resolution+refreshRate combo to QHD@240Hz. This should disable DSC.
If it doesn't disable DSC for you, it will definitely be disabled on HDMI 2.1 on new firmware(s)
The DP2.1 is backward compatible with DP1.4, that's not the issue.

Piggybacking on the SK question cuz I'm interested in the smoothness and frame pacing aspect of SK. Is there a specific config I need to setup to best frame pacing? Thanks.

Check out their wiki: https://wiki.special-k.info/Advanced/Video
The GUI, launched with CTRL+SHIFT+Backspace key combination, has tons of settings with descriptions of what they do.

Be aware that this is only a solution for games without a kernel-level anti-cheat.
Ones which do have a anti-cheat solution might flag you, you're in gray area.

[7bhsq]

So is 60hz single strobe in VRR mode just not happening anymore? Or has it been pushed back to the next firmware update?

[liquidshadowfox]

So is 60hz single strobe in VRR mode just not happening anymore? Or has it been pushed back to the next firmware update?

It sounds like nvidia added the 60 hz ULMB mode and said "this is good enough because the flicker below 75 hz is too much and we don't want to deal with a bunch of people complaining that their eyes hurt or blame our monitor for their mental anguish due to flicker". I do agree it gets really difficult to do VRR anti flicker mitigation as you get to lower refreshes. The reason they picked 75 hz as the lowest point is because flicker fusion threshold is around 72 hz (point where most people start to notice the flicker less and less) to my understanding. I still don't see why nvidia couldn't just enable 60 hz VRR and have a toggle that says "be warned this might produce eye strain over prolonged periods" and they'd need to enable it down to 55 hz, not 60 hz cause they have a 5 fps buffer (so currently setting 75 hz as minimum, pulsar disables once you go below 80 hz).