Gamma and contrast degradation on 144hz/240hz monitors

HiCZoK

Gawd
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Sep 18, 2006
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Hey everyone.

I've went through quite a few monitors lately. Two AOC AG251FG monitors and two Dell U2417H.
I wanted to give a fair chance to decent ips and fair chance to newest and greatest gsync 240hz technology after owning amva 60hz montior for about 2 years.
In short - Dell ips completely failed on all fronts. Grey blacks (poor contrast) caused by massive corner bleeding from only one corner but radiating to 1/3rd of the panel in yellow. I've tried 2 units in few months apart and both suffered from dark scenes crippling blb... and whites were pink but that's another story. IPS glow was not such a big issue as with old ips though. In general - I felt I can do better pixel response time and image quality wise at least when it comes to media consumption and dark scenes/netflix shows and games like Dark souls etc.

Now... AG251FG was freaking awesome. 240hz and motion clarity were very very good. I was running it at 240hz gsync mode and 2 units I had, had pretty bad clouding patches in the middle and all around the bezel glow. Totally Like edge-lit glowing and that is on 0 (ZERO!) % of brightness. Pics are overexposed but it was harder to capture on pic so i had to overexpose. In reality, it was easily visible in most situation. Not only in dark room.
DCeBDah.jpg

That's the reason I've returned them. It was visible in any dark scene and even on colors too. I couldn't accept it for monitor this expensive. 240hz was nice but I am not a pro player.


2 Weeks ago I've decided to try some "middle" ground solution and got LG 24GM79G. Typical 23.8" 144hz monitor. And here the interesting part starts.... I've "discovered" that the monitor looks GREAT and completely different in 60hz compared to targeted by this monitor 144hz mode.
At 60hz, the gamma is about 2.2 in the middle, contrast is exceptionally solid. I mean it's VA like perceived. This is one of the best looking solid black screens I've seen on a monitor. Great uniformity, no blb, no issues whatsoever except requiring to tinker with osd settings. That means setting brightness to 5% (120cd), gamma to mode4 and contrast from 70 to 60 because it was crushing whites. But after that it's a solid monitor.

The problems start when I switch to 100/120/144hz modes. The gamma and contrast get gradually worse. I have black screen as a wallpaper for testing purposes (and I kinda like it this way) and when changing the refresh rate, the screen gets brighter and less uniform with each step. At 144hz gamma is at 1.8, Black is greyish, clouding is made visible and blb on the left edge appears. That is a huge disappointment to me. Not only that but the strobing mode makes things even worse at any hz.
Here are pics of 60hz vs 144hz. Same settings (0% brightness, strobing off, nvidia set to full rgb). Keep in mind, it is difficult to capture.
hynMAZa.jpg

3Zxhl1p.jpg


Now my question is - Do all 23.8 monitors do that? do 24.5 monitors do that? Do 27" monitors do that? If not, then are they locked in the better looking (60hz) mode or are constantly in "degraded/overclocked" state for the lack of a better word?
It looks like if this 144hz monitor was created with 60hz in mind and achieves 144hz by overclocking and essentially forcing panel to do it and that's why it looks so much more washed out and so on.

Can anyone else test this? Not sure if I should keep looking for other monitors or be happy that I've found a good looking 60hz monitor with optional poor looking high refresh rate... I mean I use it on console to and 60hz was one of my targeted usages but I was hoping for 120hz pc gameplay... but I am using only 60hz because it looks so much better.
 
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XoR_

[H]ard|Gawd
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None of the images works for me. There is some error about image having errors.

These issues sound pretty much like those reported by owners of overclockable Korean IPS monitors.

I would be very interested to hear input from users of high refresh rate monitors.
 

HiCZoK

Gawd
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Sep 18, 2006
Messages
821
Hopefully the images are fixed now.

I don't know about high refresh rate ips monitors but if this LG had the same picture/gamma/clouding/blb quality at 144hz as it has on 60hz, it would be the best screen ever! Right now it is one of the best 60hz screens I've seen when it comes to uniformity. The 240hz aoc I had for a while looked bad all the time but I don't think it was as poor as 144hz on this lg.
I can still return the LG 24GM79G but I am afraid the next monitor I will buy will look either like that 240hz aoc or like LG at 144hz. I mean I like high refresh rates but now if it all looks like this. if so, screw it, I am staying at 60hz...
 

RPGWiZaRD

[H]ard|Gawd
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Higher refresh rate always degrates contrast especially, reviews with measurements shows this although typically it's fairly low up to around 120~144Hz. I did notice a huge contrast drop and it started to look less "sharp" on my BenQ 240Hz but I found the middleground at 144Hz + BenQ Blur Reduction (BenQ's ULMB / Strobing technique) so then I both kept the nice colors and sharp look and even better motion smoothness (when there's no big FPS drops). For me from image quality vs performance point of view, the 144Hz + strobing is the sweet spot for the 240Hz panels (other panels support max 120Hz with strobing and it's a clear difference jumping up to 144Hz) and at least the BenQ I was able to calibrate really nicely, finest TN panel I've seen by far.

Manufacturers have been pretty cheap when it comes to high refresh rates and often used a panel that is 120Hz native and then clocked it up to 144Hz or whatever. The 240Hz panels do come with better hardware that is better capable of handling higher refresh rate but I think probably whatever hardware you put in, at 240Hz it's always likely to degrade somewhat. Those 24" monitors that were overclockable to 180Hz had no better panel than typical 144Hz marketed ones and they dropped off a shitload in contrast at 180Hz, like was it below 600:1 even which is whereabouts old first generation LCDs were at!

Oh and I have no problem with uniformity on my BenQ. On my previous monitor I had a lot of BLB especially but this one has really little of it.
 
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HiCZoK

Gawd
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Well my lg does look worse on 144 than 120hz. But 120 looks worse than 60hz so it seems like it's native 60
 

igluk

Gawd
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The M240HW01 panel used in almost all 24'' 1080p gaming TN is native 120Hz.
The newer 24.5 and 27 variants, they come in native 240Hz and also native 144Hz versions.
The issue with image washing out at higher refresh rates is well documented but I don't know why that is so. It seems to only affect TN-type panels.
 

N4CR

Supreme [H]ardness
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The M240HW01 panel used in almost all 24'' 1080p gaming TN is native 120Hz.
The newer 24.5 and 27 variants, they come in native 240Hz and also native 144Hz versions.
The issue with image washing out at higher refresh rates is well documented but I don't know why that is so. It seems to only affect TN-type panels.
Probably switching time of the individual sub-pixels. Another factor could be that they might drop bit-depth as speed increases.
 

XoR_

[H]ard|Gawd
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Panel itself might be limited to some contrast ratio at each refresh rate due to some internal stuff going on and while this sucks it might as well just be the limitation of this panel type.
Gamma decrease with faster refresh rate indicate however that this monitor is just badly designed.
Even if it is panel itself that have different gamma response at each refresh rate (and it should not, panel manufacturer should correct this if this is native 120Hz panel!) then LG should make sure that gamma did not change by providing its own correction.

Isn't there any way to change gamma in monitor OSD?
Also what are the measured contrast values for 60Hz vs 144Hz?
 

HiCZoK

Gawd
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I dont have any tools but contrast seems about halved at 60 vs 144.

There are gamma setting but darkest setting needs to be used at 60hz to get 2.1/2.2... So there is no way to darken it at higher refresh rates when iy becomes about 1.8. Its 0.1 step every refresh rate step...

I wo der if there is difference between native 24.5 144hz and 240hz panels. Or is it the same panel but downclocked to 144.

That means - the flat va panels start at ridiculus 32"... So 23.8-27" is occupied by tn and ips. I am not interested in ips so I wonder if I should return lg and look for something else
 

igluk

Gawd
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I wo der if there is difference between native 24.5 144hz and 240hz panels. Or is it the same panel but downclocked to 144.

The panel models are different but other than refresh rate they have identical specs.
 

HiCZoK

Gawd
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I thought so... so essentially - those 24.5" models would not satisfy my needs. I mean the gamma and contrast are ok but they all have clouding and edge lit bleeding it seems. The edge lit blb like I've shown in first pic is apparent on ALL 24.5" gsync montors and I've seen reviews for samsung shg50 and it looked the same. No idea about 27" versions. Only seen reviews on 240hz 27" acer screen and it also had this issue. Maybe 27" 144 hz are better but due to lower ppi IO don't really care.

So the 23.8" panels might still be a way to go. That means good contrast and no clouding/blb in at least lower refresh rates or possibly at all refresh rates depending on handling by producer.

I wonder if stuff like asus pg248q would be at all comparable to LG 24gm79g. Gamma handling is up to asus at each hz step but probably contrast drop and clouding/blb appearance would be the same as lg. So for me it would be a 60hz gsync monitor... There are also benq screens which are supposedly very good.

Or due to a dynamic nature of refresh rate with gsync monitor, the timings and bad contrast/etc would be stuck in upper values all the time
 

XoR_

[H]ard|Gawd
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Ah, ok, you used test images to evaluate gamma then
I would return this display then and go with something else, even with the same panel but which have less downgrade in contrast and at least one which does not show change in gamma. Monitor going to gamma 1.8 is completely unacceptable.

Mind that while without VBR you loose a lot without 120/144Hz but with G-Sync/Freesync you do not really need that high refresh rate as even properly set up 60Hz provide great experience. It is pretty much impossible to have no stuttering in your current setup without sustaining crazy high refresh rates and at the same time adding tons of input lag from v-sync. So if you do not want to change display I would advise you to at least change GPU. Upside of having AMD card is ability to correct gamut and even if display have 8bit inputs to correct gamma in desktop without banding.
Mind that for movies/videos to display them correctly you need to have not gamma 2.2 but gamma 2.4. Also with VBR it is easier to have no stuttering during playback, another headache of fixed refresh rate displays. Same story with emulators.

Maybe go with 27"? In desktop screen door effect would be horrid but gaming at larger screens is so much better and screen door in this case due to how perception works can actually fool your mind to think that games looks better, especially older ones with blurry textures.
 

HiCZoK

Gawd
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The only 1080p gsync non 24.5" monitor is asus pg248q though. There is also 240hz gsync 27" acer but I am not sure about this one
The 1440p options are Dell 2417dg, AOC Ag241qg and then there are 27" 1440p options (tn).
All gsync options are twice as expensive as non gsync counterparts. The aoc ag251fg had no edges bleeding or couding in pcmonitors review and my 2 units had terrible issueswith this and gamma...

I have no idea what to do. I probably have to return LG and get some other TN. The point is - this LG is supposed to be the BEST looking non gsync 24" 144hz tn. Maybe on par with viewsonic which is not available here. Benq options have worse colors as people say
 

XoR_

[H]ard|Gawd
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I'd go with 1440p 27" then.
Twice expensive... still not expensive enough to suffer stuttering imho.
This is of course my opinion as I absolutely hate stuttering, input lag and inferior technology when superior technology is available and I do not have to go to the streets and sell drugs to afford this superior technology like I would need with eg. Tesla :dead:
Imho all this going with Freesync (which is basically everywhere) when having GeForce is more of a psychological barrier than anything else and while I do understand it can be frustrating I also do not understand why it would be that big of an issue to the point of not getting it.
After all when after some time you will be selling monitor you will get more money back because G-sync monitors sell for more, much more.

My 2 cents
 

HiCZoK

Gawd
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Through the years I've learned to live with just vsync and rtss. But gsync is indeed nice and removes most of stutters. Shame the quality of picture was not there on aoc ag251fg.
 

Armenius

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Have not had this issue on either of the 144 Hz monitors I've owned. Picture quality on both actually get worse the lower the refresh rate is.
 

HiCZoK

Gawd
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I don't even care for 144hz monitor anymore. I mean it's a nice bonus for pc gaming but at this point I just want good looking 60hz monitor. No matter what technology :p
Edit: LG returned, so now I am open for new suggestions anyway. How is some 60hz stuff like maybe eizo fs 2434 or ev2450 ? Theseare not popular pics but Eizo is quality, right ?
 
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viivo

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Just to add my experience with two LG34UC79G-B: 144hz is way too dark to be of use, but 120 and 100 look great with minimal input lag. Going down to 75 and 60, though, drives input lag through the roof and severely washes out colors.
 

XoR_

[H]ard|Gawd
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24" 60Hz display with best image quality would be HP LP2480ZX + HP calibration kit based (the one on i1 Display One)
You can calibrate it in hardware to perfect sRGB/Rec.709 gamut and gamma 2.2/2.4 without loosing any contrast ratio despite black point being also always calibrated thanks to controlled RGB-LED backlight (it can change colors on its own so there is never any reason to limit contrast ratio). It also have probably largest gamut found on any LCD monitor. Due to A-TW it have almost perfect viewing angles and lack pesky IPS glow making contrast ratio figure actually meaningful. It also uses very strong PWM which greatly improves motion definition compared to flicker-less panels. It is not 60Hz and I am not sure what refresh rate it is but I know I do not see the kind of smearing flicker-free monitors have. It also have 16:9 ratio making it almost the same height as 27" 16:9 monitor which is great for me :)
Flaws include rather poor font rendering caused by its ridiculously large gamut (which doesn't even matter because for perfect font rendering one buys 4K sRGB monitors anyway ;)) , 24ms input lag (so it is not a best choice for games), fan (of course they had to include fan... :hungover:) and usually only available used and usually still quite expensive. Personally I was never bothered by its flickering even when I used it as main monitor (actually LG W2420R with the same panel - I am a big fan of this tech :cool:) and find it rather 'refreshing', even very pleasant to look at.

You can however some times buy them very cheap with panels in perfect condition (not scratched). These monitors acquire over time pink tint which make people think they are broken. I bought two with pink screens for less than 300 bucks total, both calibrated perfectly and now have two best 60Hz monitors to watch videos on in reference quality. It also support 50Hz if anyone except me even cares. I use mine mostly in 50Hz :cat:

Of course there is no blb bleed, black and black is very uniform and these monitors even have built-in compensation for these things as can be seen with test images near edges where image like this one http://www.lagom.nl/lcd-test/white.php can reveal it. White screen is all white.

And that would be pretty much it regarding best 24" 60Hz monitor.
You can of course also get new Eizo CX240 which have similar feature set difference being reduced to 16ms input lag and reduced contrast ratio and reduced native gamut. EIZO does not have fancy RGB-LED backlight or speaking simpler terms: it have inferior panel. They do not make them panels like they used to :confused:

But seriously, I totally do not understand why people do not hunt for these monitors...
I like it so much I will buy another one should good condition one pop out for up to around 400$... despite already owning two :wacky:
 

HiCZoK

Gawd
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Thanks. It is not even available here. Like nonexistent. HP is not big in Poland I guess.
I am considering Eizo EV2451 or 32gk850g... lol Those couldn't be 2 more different monitors so I am in a pickle
 

DanNeely

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If all of that is a standard greeting, how many people die of old age during chatty ones. ;-P
 
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