comparison 240hz displays

Everything about displays and monitors. 120Hz, 144Hz, 240Hz, 4K, 1440p, input lag, display shopping, monitor purchase decisions, compare, versus, debate, and more. Questions? Just ask!
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sunhunter
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comparison 240hz displays

Post by sunhunter » 27 Apr 2018, 11:15

If we compare this 4 display .) AW2518Hf .) XG2530 .) XF250Q .) AG251FZ as they are lowest price 240hz today available. As i understand
AG251FZ and XF250Q are not as good because of frame skipping, bad colors, blurry compare to their opponents. acer is cheapest one (amazon).
now compare AW2518Hf and XG2530.
input lag - AW2518Hf
colors - XG2530
i think input lag problem on viewsonic is not big issue because it is still low. slightly worse compare to alienware but good enough.
motion blur - on XG2530 is close to asus one on this image.
pursuit_2.jpg
pursuit_2.jpg (44.73 KiB) Viewed 6984 times
if someone can please tell is motion blur better/worse on alienware?

Now if we look at prices (amazon) viewsonic - 380$ alienware - 313$.
is colors on viewsonic as good that u should go for it not paying attention to price and input lag?

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Chief Blur Buster
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Re: comparison 240hz displays

Post by Chief Blur Buster » 27 Apr 2018, 11:54

The left image is very close to Blur Buster's Law of 1ms = 1 pixel of display motion blur for every 1000 pixels/sec motion

Refresh time of 240Hz = 1 / 240 = 4.16666666666ms

Here is a chart I created a few years ago. It is a visual guideline for the theoretical absolute best motion clarity possible for a given persistence (and Hz ballpark). Refer to the "4ms" reference image, generated algorithmically (linear blur in graphics edit app), as your reference of the sharpest possible motion you can get on a sample-and-hold (flickerfree) display without a blur reduction mode.

Image

To get better,
-- You need higher Hz -- see Blur Busters Law: The Amazing Journey To Future 1000Hz Monitors
-- Or you need strobe-based motion blur reduction -- see Motion Blur Reduction FAQ

If you find motion blur reduction important, you should seek ULMB (sequel to LightBoost), ELMB, DyAc, Blur Reduction, etc. Make sure any monitor you purchase has a "Blur Reduction" feature. Our monitor lists tell you which monitors have blur reduction modes.

Most good 240Hz TN monitors will closely match the left image of the TFTCentral image you posted. My Acer XB252Q and ViewSonic XG2530 does. The early AOC (FreeSync version) had worse blur and has an unfixed frameskipping bug. The GSYNC version of AOC is much better.
-- If you're doing FreeSync, I like the ViewSonic XG2530 the most.
-- If you're doing GSYNC, most of them are very similar to each other. Jorim's GSYNC 101 tested the XB252Q.
-- If the Blur Reduction setting is the most important criteria, then LG 27GK750-B and BenQ XL2546 have 240Hz capable strobe backlights. LG beating the BenQ slightly in strobe crosstalk when doing the Large Vertical Total tweak.
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sunhunter
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Re: comparison 240hz displays

Post by sunhunter » 27 Apr 2018, 12:41

thank you for detailed answer, so xg2530 has not ulmb but has a good blur reduction. it will be close to 4ms persistence yes?
i'm looking for display near 350$ and i can not find with ulmb for this price range. what do you think about alienware? some pros does not like but i can not find any reason for this. i read on this forum that alienware blur reduction is close to asus.
so if we drop acer, you think that xg2530 worth extra 60$ over alienware?
and there is any other options ~350$ better than this two?

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RamenRider
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Re: comparison 240hz displays

Post by RamenRider » 29 Oct 2018, 03:08

So what's the best 240hz monitor to buy? Or should I wait for newer ones cause these gen 1 monitors aren't up to par yet.

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Re: comparison 240hz displays

Post by Chief Blur Buster » 29 Oct 2018, 10:59

The best 240Hz monitor tends to depend on priorities.

- Do you want FreeSync?
- Do you want G-SYNC?
- Do you want motion blur reduction modes (ULMB)?
- Do you want something usable for professional eSports? (lowest lag above all else)
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Friard
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Re: comparison 240hz displays

Post by Friard » 31 Oct 2018, 18:54

Chief Blur Buster wrote:The best 240Hz monitor tends to depend on priorities.

- Do you want FreeSync?
- Do you want G-SYNC?
- Do you want motion blur reduction modes (ULMB)?
- Do you want something usable for professional eSports? (lowest lag above all else)
What 240hz has the lowest lag above all else? I'm interested

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RamenRider
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Re: comparison 240hz displays

Post by RamenRider » 06 Nov 2018, 05:54

Yeah that's what I want to know as well.

I read the comments here:

"The problem with these new 240hz panels is the input lag. All reviews around the web shows the screen lags at 15ms to 16ms. Sure, when you are using 240hz you divide that for 4 (240/60), ending up with 4ms input latency, wich beats any offer on the market. Be it 60hz or 144hz.

The thing is, a good and fast 144hz monitor, like the famous LG 24GM79 (240€) or Asus MG248Q (300€), both rated at around 9.7ms input lag (dividing by 2,1), wich gives effective 4,6ms input lag. Now compare 4,6ms vs 4ms. Is that big advantage for 240hz considering you spent 500 bucks? And also taking into account that most games won´t get past 200fps (CS Go and OW can do it, most of the other games cant) thus increasing input lag even more. To me it isn´t worh it at all.

Adding to that, if you ever use that monitor with a console at 60hz, input lag will be too high aswell. The only real advantage 240hz gives right now is the motion clarity, wich is clearly improved over 144hz. But that doesn´t justify anything. I still prefer a lower input lag 144hz monitor, by far.

When 240hz tech matures and we get decent input lag screens (ranging from 9,5ms to 11ms like any good 144hz monitor), then we talk."

https://on-winning.com/240-hz-monitor-worth-difference/

open
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Re: comparison 240hz displays

Post by open » 06 Nov 2018, 09:38

I dont think we have a clear answer on what 240hzs have the lowest input lag. We need someone with a good testing methodology to test all of them.

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Re: comparison 240hz displays

Post by Chief Blur Buster » 06 Nov 2018, 11:33

RamenRider wrote:Yeah that's what I want to know as well.

I read the comments here:

"The problem with these new 240hz panels is the input lag. All reviews around the web shows the screen lags at 15ms to 16ms. Sure, when you are using 240hz you divide that for 4 (240/60), ending up with 4ms input latency, wich beats any offer on the market. Be it 60hz or 144hz.

The thing is, a good and fast 144hz monitor, like the famous LG 24GM79 (240€) or Asus MG248Q (300€), both rated at around 9.7ms input lag (dividing by 2,1), wich gives effective 4,6ms input lag. Now compare 4,6ms vs 4ms. Is that big advantage for 240hz considering you spent 500 bucks? And also taking into account that most games won´t get past 200fps (CS Go and OW can do it, most of the other games cant) thus increasing input lag even more. To me it isn´t worh it at all.

Adding to that, if you ever use that monitor with a console at 60hz, input lag will be too high aswell. The only real advantage 240hz gives right now is the motion clarity, wich is clearly improved over 144hz. But that doesn´t justify anything. I still prefer a lower input lag 144hz monitor, by far.

When 240hz tech matures and we get decent input lag screens (ranging from 9,5ms to 11ms like any good 144hz monitor), then we talk."

https://on-winning.com/240-hz-monitor-worth-difference/
Lag of a screen is a complex topic, please see my older post here.

240Hz screens also diverges in scanout velocity between cable scanout speed and panel scanout speed, so there can be a lag-differential asymmetry for the top edge of the screen versus bottom edge of the screen. With a Leo Bodnar with a 60Hz (slowscanning) 1080i signal, the top and bottom edge usually as a ~16ms differential (refresh cycle transmission over cable, with panel refreshing top-to-bottom in sync with it) during VSYNC ON lag testers such as Leo Bodnar. However, doing a 60Hz 1080p on a 240Hz monitor show only a ~4ms differential. That's because the monitor has an internal scanconverter to buffer the slow scanning 60Hz (cable) and then output the scanout at the panel's native fixed scanout velocity (1/240sec top-to-bottom refresh). To speed up the scanout, it becomes necessary for the 240Hz monitor to partially buffer the refresh cycle before beginning the refresh-cycle scanout. This buffering behaviour occurs at low Hz, but the workaround might also theoretically be adding more lag at the top Hz on 240Hz. However, the fastest 240Hz monitors keep up pretty well -- e.g. the XL2546 is pretty low lag. Ideally there should be no buffering-like behaviour at the max Hz at least, since the cable Hz is the same as the panel's native scanout velocity. Other panels are variable scanout velocity, like most 144Hz 1080p panels. (the 1440p panels are a different story however -- they got internal scan-velocity conversion behavior; sigh).

While there's some issues with some buffering -- 240Hz monitors still vastly outperform during VSYNC ON operation if you follow a few rules. For 60fps content, the lag savings of 240Hz versus 60Hz is a whopping ~12ms max, which can overcome some buffering-related lag differentials if it's only a tiny fraction of a refresh cycle. You can fix this via either using GSYNC (e.g. 60fps at 240Hz) or via Quick Frame Transport tricks (e.g. Vertical Total 4320 -- a blanking interval about 3x the size of visible vertical resolution) at 1080p, to speed up the refresh-cycle delivery, to make the panel scanout velocity in sync with the cable scanout velocity, keeping your 4ms top-vs-bottom edge, and getting a low-lag hacked "60Hz custom resolution" on a 240Hz monitor. (Though it's more complex than a 60fps cap at 240Hz).

SOOOO many tricks to raise/lower lag on 240Hz monitors because of the added complexity of asymmetric cable-vs-panel scanout velocities. You can't divide a lag number by 4 because of that factor, unfortunately -- some panels are fixed-scanout (needs internal buffering for scanout-velocity differentials) and some panels are variable-veolocity scanout.

Also, lag to GtG percentage is an issue in apples vs oranges measurements. RTINGS have numbers accurate for VSYNC OFF, while TomsHardware has numbers accurate for VSYNC ON. Humans can still see a pixel far less than GtG50% (when a pixel is already grey during the pixel transition from black to white), but lots of lag testers trigger early (e.g. GtG5%) or late (e.g. GtG100%). The lag difference of GtG5% and GtG100% can be well over 10 milliseconds, especially for some colors (e.g. some colors are laggier than others). So lag measurement science is quite imprecise.

In some metrics, the 240Hz monitors outperform, while in other metrics, the 240Hz monitors underperform. If you're looking for lower lag during VSYNC ON, all 240Hz monitors (when run at 240Hz scanout velocity). A 240Hz monitor may be lower lag in top-vs-bottom difference (which makes them superior for whole-refresh-cycle-at-once situations such as VSYNC ON or G-SYNC) but higher lag in absolute pixel-in-GPU-thru-pixel-on-screen due to a buffering stage (which unfortunately affects VSYNC OFF). So that means a 240Hz monitor may massively outperform in lag in G-SYNC but underperform in lag in VSYNC OFF when compared against a 144Hz monitor, because of different lag bottlenecks showing up.

Isn't monitor engineering fun, eh?

Disclaimer: I work with multiple monitor manufacturers
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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kabforks
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Re: comparison 240hz displays

Post by kabforks » 19 Nov 2018, 09:38

Hi Chief Blur Buster, do you have any examples of a monitors which

* "may massively outperform in lag in G-SYNC but underperform in lag in VSYNC OFF when compared against a 144Hz monitor"

or

* A 240Hz monitor may be lower lag in top-vs-bottom difference (which makes them superior for whole-refresh-cycle-at-once situations such as VSYNC ON or G-SYNC) but higher lag in absolute pixel-in-GPU-thru-pixel-on-screen

I am in the market for a 240hz with extremely low input lag, with VSYNC OFF, GSYNC OFF. It's primary use is competitive FPS. Blur reduction techniques may come in handy, but it's not a priority.

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