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Why I'm done with 240hz

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Re: Why I'm done with 240hz

Postby Chief Blur Buster » 04 Feb 2019, 16:26

jorimt wrote:Hm, yeah, only G-SYNC monitors w/modules use variable overdrive (99% of FreeSync monitors do not), so FreeSync may have just exasperated this overdrive limitation at 240Hz w/lower framerates anyway.

In keeping good relations to AMD (who, along with NVIDIA too, reads Blur Busters forums from time to time, as long-time lurkers)...
....I'll just add that by "FreeSync", you meant "...The historical lack of dynamic overdrive in most FreeSync monitors..."
Yeah, that's me being Switzerland again.

jorimt wrote:is it using the same internal overdrive preset parameters at a physical 144Hz scanout (6.9ms) as it is at a physical 240Hz scanout (4.2ms)? I'm assuming it is, since monitor manufacturers don't expect someone who buys a 240Hz panel to underclock it to 144Hz right off the bat, but (while I'm assuming some reviewers have probably tested this very scenario) it would be interesting to confirm.

Actually, I think some of them don't even bother to overdrive re-tune for 144Hz. Many of the 2017-era and 2018-era 240Hz monitors are fixed horizontal scanrate.

They are internally scanrate-converting any refreshrate to full 1/240sec scanout velocity. While this made it simpler to introduce the first 240Hz panels, this has some unintended side effects on input lagency (monitor motherboard buffering a slow-scanning 60Hz video input for a fast-scanning onto panel at 1/240sec) as well as overdrive tuning differences since tuning for a 144Hz @ 1/240sec scanout velocity is slightly different from 144Hz @ 1/144sec scanout velocity.

Correct, different ovedrive is currently being used on my GSYNC monitor 144Hz versus 144fps@240Hz.
The GSYNC's dynamic overdrive looks different on my GSYNC monitors, IIRC consistent 144fps@240Hz tended to look a bit better than fixed-Hz 144Hz on the same GSYNC monitor. So yes, it seems to be clearly using a different overdrive formula in these modes (possibly NVIDIA's overdrive formulas in GSYNC mode, and manufacturer's overdrive formulas in non-GSYNC mode).

Whether one of the two manages to match an average 144Hz monitor (as a baseline), is indeed meritworthy of further testing.

Still.... Many of us are pleased with our 240Hz monitors, imperfections nonwithstanding.

The 240Hz GSYNC monitors that I've seen generally looked better (at lower frame rates) than the 240Hz FreeSync monitors whenever GSYNC was enabled. It actually looked better than turning off GSYNC and trying to use VSYNC OFF. Or trying to use lower-Hz fixed-Hz (e.g. fixed 144Hz versus GSYNC 144fps@240Hz) -- the variable overdrive tuning was sometimes superior to the fixed overdrive tuning.

I believe (in time) one of us will really need to do tests of all the overdrive quality at all the various framerates during VRR. It's very hard to automate but it is something that will need to be done.

There certainly seems to be some issues with overdrive all over the place (especially in monitors without dynamic overdrive). And reasons need to be found -- whether it's the panel fault or the lack of overdrive tuning, etc -- why it is bothering a subset of people -- even as it is not bothering the rest of us.

Some of us are more sensitive to other display effects. Absolute Lag. Latency Uniformity (along panel surface). Motion Blur. Flicker. Ghosting. Coronas. Brightness. Smoothness. Frameskips. Stutters. Tearing. Etc. Everybody's vision sees differently and it's pretty clear that some people are more sensitive to the teething problems of early 240Hz monitors (being 240Hz introduced barely two years ago).

I've alluded to this a year ago already, what I take issue is the blanket global "240Hz is worthless" posts which I will definitely go on the warpath against. Full stop. Period. However. Let's look at this. As long as you're avoiding global-blanketism, I certainly appreciate how Notty_PT worded his final sentence in his first post "This isn´t by any means an universal truth. This is my opinion, point of view and personal experience. This thread is only telling you that to me 240hz weren´t worth it".

As long as we're accepting of the different things that humans are sensitive to, I certainly have no problem agreeing that there are teething problems in the 240Hz monitors, maybe moreso than some of us would have expected. There's certainly problems in some of them that affects some people. But it isn't affecting all of us -- for some of us, benefits of 240Hz massively outweighs things we aren't sensitive to. Certainly, this isn't universally true for everybody, but it certainly isn't universally false for everybody. It belies the fact our vision are bothered by different kinds of limitations and also other variables (like enabling GSYNC ON / versus using fixed-Hz, etc)

We can at least all agree that monitors need to keep getting better over time (and they should!).
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Re: Why I'm done with 240hz

Postby jorimt » 04 Feb 2019, 16:36

boykale wrote:How did you capture it? I mean I want to test my monitor as well. Did you just record a video without any setting?

Nothing super fancy; It just took a couple dozen well timed passes of the Note 3 camera app's built-in photo burst mode with default (auto) settings (I believe; it's been a while, might have used a specific ISO setting) using a $100-ish camera rail.

You could attempt a video or use burst-mode freehanded, but it's even more difficult that way. After some practice though, freehand capture can give you an approximate representation of what your display looks like in motion in person, so long as the tracking guides are relatively straight.

Also, higher monitor refresh rate = easier capture.

The Chief can share far more than I on this subject. There's a HOWTO available on this as well:
https://www.blurbusters.com/motion-test ... it-camera/

Chief Blur Buster wrote:There certainly seems to be some issues with overdrive all over the place (especially in monitors without dynamic overdrive). And reasons need to be found -- whether it's the panel fault or the lack of overdrive tuning, etc.

Am I also correct in assuming the reduced overdrive quality (at the max fixed refresh rate on many of these 240Hz models), is due, in part, to the faster scanout at 240Hz with these 1st gen panels, which probably don't have that much of a reduction in native GtG levels when compared to the lower refresh panels?

As in, 4.2ms gives overdrive even less time to make it's adjustments, which means overdrive timings have to be even tighter at 240Hz to reach the same results as they do at lower refresh rates, and since the average GtG levels (even with overdrive) on 1st gen 240Hz panels apparently aren't always low enough to accommodate (aka native panel GtG fade is perhaps too great), we get this, or is that not (or only partially) a factor?
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Re: Why I'm done with 240hz

Postby Chief Blur Buster » 04 Feb 2019, 17:30

jorimt wrote:
boykale wrote:How did you capture it? I mean I want to test my monitor as well. Did you just record a video without any setting?

Nothing super fancy; It just took a couple dozen well timed passes of the Note 3 camera app's built-in photo burst mode with default (auto) settings (I believe; it's been a while, might have used a specific ISO setting) using a $100-ish camera rail.

You could attempt a video or use burst-mode freehanded

There's now a much easier HOWTO for laypersons, for hand-waved smartphones:
New Easy Free Pursuit Camera: Smartphone. No rail needed.

Practically any reader can do that now with that technique. However, reader interpretation of results can be distorted by things like the accuracy of the pursuit. There is always a subjective factor and smartphone auto-everything behaviours can fight against this. It helps to use a recent smartphone and a 3rd party smartphone app (fixed exposure/fixed focus/fixed color balance/fixed ISO) during video recording, and aim for enough pursuits that you manage to capture subpixel pursuit accuracy. Good practice with hand-waves can result in pursuit photos nearly as good as rail-based pursuits.

jorimt wrote:Am I also correct in assuming the reduced overdrive quality, is due, in part, to the faster scanout at 240Hz with these 1st gen panels, which probably don't have that much of a reduction in native GtG levels when compared to the lower refresh panels?

Not necessarily. You can get good overdrive tuning on those in theory, but a faster scanout is often associated with lower LCD quality -- much like how many 144Hz monitors often did better colors at 60Hz.

jorimt wrote:As in, 4.2ms gives overdrive even less time to make it's adjustments

Overdrive is simply overshoot color values to help speed a color transition, e.g. using pixel grey value 160 to accelerate a pixel grey value from 0 to 128.

<Blur Busters Technology Pandora Box>
However, fast scanout means less microseconds per pixel row refreshing, which means less time injecting voltage into a pixel row to begin the molecule momentum (LCD = Liquid Crystal Display = molecules that rotate to block/unblock polarized light... Wikipedia | HowStuffWorks | ExplainThatStuff).

The GtG pixel transition is in motion long after the pixel state-change voltage has already moved onto refreshing next pixel row, creating the lagging-behind GtG fade zone effect you see in the high speed videos at http://www.blurbusters.com/scanout

Only one row (or few) of pixels is receiving a voltage surge at a time (changing the state of the pixel) -- and the pixel GtG momentum of the physical molecules of the LCD pixel -- continues for a while afterwards (assisted by the active matrix transistors at the pixels) long after the pixel-state-change voltage has moved onto the next pixel row. The GtG fade zone is a lagbehind effect.

The human eye sees the average pixel color of a continually-transitioning pixel. If the pixel is too slow or fast, spending more time emitting the wrong color, you're seeing ghost or corona effects. You're seeing a difference in trailing color versus leading color as seen in images at LCD Motion Artifacts 101, and LCD Overdrive Artifacts. Rather than symmetrical motion blur at both leading and trailing edges of motion. The game of overdrive is to try to balance the undershoot/overshoot color so it balances out to being equal to the final pixel color as early as possible, with minimum artifacts. The briefer the scanout, the more overdrive overshoot you may need for correct pixel color values.

Panels are getting faster and faster (0.5ms) and that's very badly needed to keep ghosting down at 240Hz, so I'm a strong believer in 0.5ms (and even 0.25ms and 0.1ms) in keeping up the Refresh Rate Race. 1ms GtG matters virtually none for 60Hz but 1ms GtG is a noticeable chasm of a limitation at 240Hz+. 1ms GtG or faster becomes hugely important in the Refresh Rate Race to future Retina Refresh Rates, where we really need pixel transitions to be a tiny fraction of a refresh cycle.

Now, one effect is when I overclock my LCDs, pixel GtG actually slows down. For example, when I overclock one of my 100Hz VA panels to 110Hz VA, it actually generates worse GtG than even 85Hz! So overclocking sometimes actually causes GtG to get a bit dirty/inaccurate/slow again and the amplified ghosting starts to appear. Oftentimes, 165Hz/180Hz looks no better than 144Hz on overclockable LCDs, while using native 240Hz actually looks much cleaner (at the full 240Hz anyway).

Now,

Faster velocity scanout (even at same Hz) means few microseconds per pixel row -- of voltaging a pixel row, which means you have to be much more aggressive with overdrive (e.g. maybe using pixel grey value 200 instead of 160 in order to accelerate a pixel grey value from 0 to 128). And at fullbrights, you can't go above pixel grey value 255 to try to accelerate a GtG pixel grey transition from 0 to 250. So that's why you often have worse overdrive problems at the dark colors and with bright primary colors (like TestUFO's cyan), than with the middles.

Fixed-velocity scanout (even if faster) can make overdrive tuning a little easier since one overdrive tuning formula may actually work with all refresh rates -- but it may be a "jack of all trades, master of none" overdrive formula, often a simplistic Overdrive Gain (simpler), rather than a full Overdrive Lookup Table (superior). Sometimes both techniques are combined.

Now imagine you're trying to overdrive a grey color value from 0 to 250, and the maximum allowed value for a pixel is 255. So you're limited in how fast you can overdrive all the way to the end of the pixel color range. Sometimes you're slamming against the floors/ceilings, and the only way to improve overdrive (and reduce strobe crosstalk) is simply an intentional dynamic range reduction (increase digital black levels above complete-black, and decrease digital white level below complete-white).

That way, the only time a pixel is asked to go below black or above white, is the intermediate overdrive values. e.g. if you're in pixel greyscale (per color channel) color range 16-235 and you want to speed up a pixel transition 64 -> 235, the screen can simply use an overdrive value of 255 (the max) to speed up the transition from grey shade level 64 to grey shade level 235. This is a luxury you don't get when you use full contrast ratio of an LCD.

The intentional dynamic-range-reduce trick can dramatically decrease ghosting on 240Hz monitors if you are willing to sacrifice 10% of your contrast ratio to creating overshoot headroom for the overdrive. (Digital dynamic range reduction via adjusting sliders in NVIDIA Control Panel, not via monitor adjustments, unless you're very sure that the adjustments are being done digitally and interacts properly with its overdrive). This is also why LightBoost had crappy colors; to reduce strobe crosstalk. But it also helps 240Hz ghosting effects to an extent too.

Few people understand overdrive well enough to realize that intentional slight reduction of contrast ratio (to 95% or 90% of original range) actually fixes 90% of ghosting issues, especially with good dynamic overdrive on several true-GSYNC displays running on NVIDIA products with GSYNC enabled. This can be a potential solution for the ghosting/corona sensitive.

Also, making sure panel is warmed up to room temperature. Cold LCDs ghost more than warm LCDs. By a wide margin. It's winter time in the Northern Hemisphere, and ghosting complaints always increase during winter than during the summer. This is a bigger issue with VA panels (even a 5 degree lower temp is human noticeable as extra ghosting in darks). But also affects IPS and TN to a lesser extent.
</Blur Busters Technology Pandora Box>

TL;DR: The best, lowest ghosting I've seen on current 240Hz monitors have generally been true-GSYNC monitors running with dynamic overdrive, after 60 minutes warm up (panel temperature matches its original overdrive tuning temperature), with digital contrast ratio in NVIDIA Control Panel reduced to roughly 90-95% of original range (to give better overdrive overshoot headroom).
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Re: Why I'm done with 240hz

Postby Notty_PT » 04 Feb 2019, 17:53

jorimt wrote:
yehaw wrote:I wish I could recall for that specific test, but I can't remember. What I do remember though, was trying it with G-Sync on/off for extended gaming sessions and I still developed strained eyes after a while and could see the same blurring, so I don't think it helped much at improving, or at least to where my eyes could see a difference in the blurring. And the rest of the other 240hz panels I've tried were all FreeSync, so I can't give feedback on the VRR for those, as I have an NVIDIA gpu (was before the FreeSync update w/ NVIDIA).

Hm, yeah, only G-SYNC monitors w/modules use variable overdrive (99% of FreeSync monitors do not), so FreeSync may have just exasperated this overdrive limitation at 240Hz w/lower framerates anyway.

As far as I'm aware, overdrive presets are tuned to the max refresh rate of the monitor, and are fixed at those parameters, regardless of framerate during non-VRR operation. And, at best, even G-SYNC would probably only be using the fixed 240Hz overdrive preset(s) as a base to make it's adjustments at lower framerates/refresh rates, which means the overdrive during VRR would only look as good as it does at max Hz.

What I am interested in knowing specifically with these 240Hz monitors, is if any of them have separate overdrive parameters at lower fixed refresh rates that visibly adhere closer to the overdrive performance of the native <165Hz panels.

For instance, if you take a 240Hz monitor, set it to a physical 144Hz maximum in the control panel and do motion tests, is it using the same internal overdrive preset parameters at a physical 144Hz scanout (6.9ms) as it is at a physical 240Hz scanout (4.2ms)? I'm assuming it is, since monitor manufacturers don't expect someone who buys a 240Hz panel to underclock it to 144Hz right off the bat, but (while I'm assuming some reviewers have probably tested this very scenario) it would be interesting to confirm.

@Notty_PT, have you ever tried this specific scenario?



I did. Everytime I play Battlefield or another demanding game that has no chance of sustaining 200fps+ I either created custom 170hz 165hz refresh rates or used 144hz. The overshoot is awful in all the models I tried it at those lower refresh rates. Tbh the overshoot is already not optimal at 240hz but at lower hz it gets even more obvious. Some 144hz monitors have same behaviour when set at 60hz, but a lot of them dont. Viewsonic xg2402 for example, with a ps4 behaves correctly.
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Re: Why I'm done with 240hz

Postby Chief Blur Buster » 04 Feb 2019, 18:02

Tricks To Improve Ghosting a Little Bit

Next time anyone in this thread tests out a 240Hz monitors, please test-out the following:
  1. Full dynamic overdrive enabled (i.e. NVIDIA's flavour of GSYNC enabled, GSYNC ON, to allow dynamic overdrive), or a monitor that has better overdrive tuning at different refresh rates (e.g. XG248Q)
  2. If it is winter where you are and your room is cold, make sure that your panel is warmed up first (run continuously bright for 30-60 mins). Cold = more ghosting.
  3. Intentional dynamic range reduction via NVIDIA Control Panel (to create overdrive overshoot room to reduce ghosting/coronas). Reduce to roughly 90 percent of original contrast ratio. You'll need to fiddle with both "Contrast" and "Brightness" to make sure both blacks-brightening AND white-darkening occurs at the same time. Or simply use the "HDTV Range" setting (16-235) if that setting is accessible. Make sure blacks are digitally brighter than full-blacks. Make sure whites are digitally dimmer than full-whites. This gives overdrive overshoot headroom to help the dynamic overdrive reduce overdrive artifacts better over a wider range of colors.
It may not solve all problems for the most-sensitive people, but this can reduce ghosting/corona visibility by more than 50%, and in some cases, by more than 90% (especially when all above tips are combined together).
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Re: Why I'm done with 240hz

Postby jorimt » 04 Feb 2019, 20:44

Notty_PT wrote:I did. Everytime I play Battlefield or another demanding game that has no chance of sustaining 200fps+ I either created custom 170hz 165hz refresh rates or used 144hz. The overshoot is awful in all the models I tried it at those lower refresh rates. Tbh the overshoot is already not optimal at 240hz but at lower hz it gets even more obvious.

Good to know. Were these all G-SYNC or FreeSync models, or a mix?
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Re: Why I'm done with 240hz

Postby Notty_PT » 05 Feb 2019, 02:24

I had same results on both PG258Q (natively Gsync module monitor) and all the other FreeSync ones. At any refresh rate lower than 240hz, even 200hz, the overshoot was unaceptable for my eyes, with the PG258Q still being better at lower refreshes, but still worse than any good 144hz monitor.

Just want to add another interesting info. Today ReSpawn released their new game, based on titanfall, Apex Legends, Battle Royale game. They implemented an internal (and very good/precise) 144fps cap and no one can exceed that value no matter what tweaks, monitors or CPUs are being used. I also noticed how some modern engines are unstable at 240fps. I don´t think Devs optimize their engines taking 240hz into account, at all, and this is another con. Same thing happens with Blackout, for example. On Battlefield V you can be alone on the server looking to the sky without moving, and your fps will float between 160 and 240 for no reason.

144hz is established as the norm for now even by developers.
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Re: Why I'm done with 240hz

Postby jorimt » 05 Feb 2019, 09:59

Notty_PT wrote:I had same results on both PG258Q (natively Gsync module monitor) and all the other FreeSync ones. At any refresh rate lower than 240hz, even 200hz, the overshoot was unaceptable for my eyes, with the PG258Q still being better at lower refreshes, but still worse than any good 144hz monitor.

On the PG258Q, when you say "lower refreshes" do you mean in G-SYNC mode at 240Hz with lower than 200 framerates (because in this instance, it's always a 4.2ms scanout, but G-SYNC dynamically adjusting the amount of times it repeats this 4.2ms cycle per second to "change" refresh rate), or does "lower refreshes" mean you were actually lowering the refresh rate manually?

Or did you try both of the above with and without G-SYNC?

<offtopic>

Notty_PT wrote:Today ReSpawn released their new game, based on titanfall, Apex Legends, Battle Royale game. They implemented an internal (and very good/precise) 144fps cap and no one can exceed that value no matter what tweaks, monitors or CPUs are being used.

I actually downloaded it last night and played a few matches. But at 1440p G-SYNC, even with the specs in my sig (the 1080 Ti currently matches or outperforms the RTX 2080 by a tiny margin in most games, mind you), at max settings at least, I was only averaging in the low 100's in the training map, and the low 80's in the game itself (just 60 FPS during the initial drop-ins), so I haven't experienced this "144" cap much myself.

The game is currently extremely GPU heavy, and the graphics settings, even at lowest, don't improve performance as much as I'd like to see. It's early though (and it's based on the Source engine, no less, oof), so it could improve in time.

</offtopic>
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Re: Why I'm done with 240hz

Postby pox02 » 05 Feb 2019, 10:23

Notty_PT wrote:I had same results on both PG258Q (natively Gsync module monitor) and all the other FreeSync ones. At any refresh rate lower than 240hz, even 200hz, the overshoot was unaceptable for my eyes, with the PG258Q still being better at lower refreshes, but still worse than any good 144hz monitor.

Just want to add another interesting info. Today ReSpawn released their new game, based on titanfall, Apex Legends, Battle Royale game. They implemented an internal (and very good/precise) 144fps cap and no one can exceed that value no matter what tweaks, monitors or CPUs are being used. I also noticed how some modern engines are unstable at 240fps. I don´t think Devs optimize their engines taking 240hz into account, at all, and this is another con. Same thing happens with Blackout, for example. On Battlefield V you can be alone on the server looking to the sky without moving, and your fps will float between 160 and 240 for no reason.

144hz is established as the norm for now even by developers.


So true take for example black ops 4 this game never reach 240 fps consistant thats why on 144hz panles will look better :mrgreen:
monitors xg258q aw2518hf 27GK750F-B pg248q xg240r lg w2363d-pf xb270hu
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Re: Why I'm done with 240hz

Postby Chief Blur Buster » 06 Feb 2019, 02:40

pox02 wrote:So true take for example black ops 4 this game never reach 240 fps consistant thats why on 144hz panles will look better :mrgreen:

Be noted that there are also a lot of inconsistency between the best 144Hz and worst 144Hz panels.
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       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
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