Why do [some] 240HZ monitors have more lag than 144HZ AHVA

[Chief Blur Buster]

I certainly do talk to other lag testing websites.



Lag measurement standardization & disclosure ideas, as discussed above, are among topics discussed.

They are not the only ones I talk to. Blur Busters will be helping pave the way for improved disclosure of lag-testing methodology.

[Chief Blur Buster]

Nontheless, GtG lag is sometimes high subjective (human sensitivity varies), but the best industry standard for lag stopwatching is either GtG10% or GtG50%.

GtG10% because the photons are visible by then. 10% of the way from black to white is a dark gray. That's still visible. And manufacturer GtG response measurements are typically from 10% through the 90% point. So the GtG 10% point lines up very well with that.

GtG50% because it is a midpoint of fairness and is usually extremely close to GtG10% on many monitors (within 1ms) so reasonably close to human subjectivity.

Yet, one should keep in mind that GtG10% or GtG50% usually refer to momentary luminance levels. It is not that, at the time the luminance curve crosses the 10% mark, we actually can perceive a 10%-gray already; the over-all luminance profile has to be taken into account as well. This becomes especially problematic when using the numbers for comparing screens with very different luminance profiles (CRT vs. LCD/continuous backlight vs. LCD/strobed). Moreover, detecting some white digits on a black background is rather different from any real-life situation. All in all, it is very difficult to come up with a perceptually meaningful measure, which doesn't mean we shouldn't try (see also https://display-corner.epfl.ch/index.ph ... #Input_lag).

Very good comments. Lots of thoughts.

My opinion is that sites should disclose GtG% for their lag stopwatching process. Adding vision stimuli estimates is tough to add to lag tests,

Mentioning the sync mode and frame rate is also useful info for a lag test. Not many users know that SMTT 2.0 is a 1000fps VSYNC OFF tester (that is visually interpreted as a differential between two displays) and that Leo Bodnar is a 60fps/60Hz VSYNC ON lag tester that is electronically interpreted (beginning from VBI, ending stopwatch at an unknown point in the GtG cycle). The testing concepts of either are valid. Yet they produce apples-vs-oranges lag numbers that can sometimes be tens of milliseconds apart. And that confuses the heck out of users.

TFTCentral uses SMTT 2.0. DisplayLag.com uses Leo Bodnar. It's noteworthy that CS:GO players will find Leo Bodnar numbers (or other VSYNC ON lag testers that use VBI to start the stopwatch) mostly useless, unlike competitive console players where Leo is very helpful (since consoles are typically 60Hz VSYNC ON). So improving the disclosure to have MORE disclosure about lag test process is now going to be increasingly important to know how useful the lag numbers are.

Sometimes different colors have different lag. Possibly even expanding disclosure to also disclosing the color pair used (e.g. white->black) for lag test, since some color pairs have more lag than others due to slower GtG. Particularly VA panels, lag of transition between two dark grays can benchmark extremely high. This can lead to situations where a VA panel published less laggy than IPS (black->white), a certain panel may actually end up MORE laggy for a dark dungeon game (gray10%->gray20%). And yes, as StrobeMaster says, reduced human sensitivity to greys (more time for greys to cause a stimuli than white) amplify this issue too.

[dhaine]

that's a good question, according to tftcentral, acer xb270HU would be better for a purely competitive gamer (so not taking account anti blur stuff) at 144 than even 240hz monitors ? Well the blur reduction with 240hz even without blur reduction mode is a bonus that probably gains edge over 1,5ms difference from their chart (acer xb270hu vs pg258q)

[Chief Blur Buster]

that's a good question, according to tftcentral, acer xb270HU would be better for a purely competitive gamer (so not taking account anti blur stuff) at 144 than even 240hz monitors ? Well the blur reduction with 240hz even without blur reduction mode is a bonus that probably gains edge over 1,5ms difference from their chart (acer xb270hu vs pg258q)

Blur reduction, indeed, gains a competitive advantage that outweighs input lag sometimes (in certain games, usually OTHER than CS:GO). Sometimes not. You just have to know how to use the blur reduction mode in a way that outweighs its tiny lag.

It is explained at Properly Using ULMB Beautifully or Competitively

[hkngo007]

Hello,

Just wanted to share my personal experience on this matter as I have:
1. TN 120hz gaming monitor - Samsung S27950D (used this for about 6 years)
2. IPS 165hz gaming monitor - Viewsonic XG2703-GS (used this for about 1.5 years?)
3. TN 240hz gaming monitor - ASUS PG258Q (used this for about .5 year?)
4. IPS 165hz gaming monitor - ASUS PG279Q (this is my friends, but I've used it on severaaal occasions)

I'd like to confirm so far that indeed, the 165hz (OC'd) IPS gaming monitors above have lower input lag/signal processing than the 240hz TN monitor. This is unfortunate for me and I'll explain my failure on this shortly.

Just FYI, I've played FPS shooters for like 20 years, from CS 1.5, to CS 1.6 -> CS GO, Battlefield 3,4, 1, Left for dead 2, Team Fortress 2, Killing floor 2.

So my latest purchase was the PG258Q. Prior to this purchase, I was using the IPS 165hz. The experience with the IPS 165hz was great visually because it was 1440p, better angles and colours, but input lag wise it felt pretty similar to my 120hz in this department but was good. Motion blur was bad, I immediately noticed significantly more blur going from 120hz TN to 165hz IPS (but I got used to it eventually). My gaming performance is probably about the same overall but the enjoyment has increased due to better details from resolution and colours and viewing angles.

I started to get a bit more interested in monitors at this point, and obsessed with the hertz and TN vs IPS and all that good stuff and came across blurbusters own article on GSYNC/input lag which was very detailed (although I didn't understand it for ages because my brain is just stupid that way), and also read a lot of reviews of monitors from TFTcentral, Tomshardware, PCmonitor Info, Battlenonsense (and some other random ones).

In the end, I got sucked into the high hertz marketing and didn't fully understand the elements of input lag that point in time, such as signal processing which was the most significant factor for me (and TFT central had this captured quite well), opposed to pixel response time (blurring etc). It didn't help that different sites used different methodologies as well.

Ultimately I relied on Tomshardware (lowest black to white time) + Battlenonsense (low button to pixel delay) + blurbuster (higher hertz = lower delay (scanout time?))which showed very low levels of "lag" for the PG258Q. I went and bought the PG258Q.

Here are my experiences so far (also I have a 1080ti + play on low and can sustain 200-500 FPS easily):

Pros of the PG258q compared to IPS 165hz
- the image/my movements felt a lot smoother
- i could see a lot better when scanning around
- in some games, or situations within the same game, I appeared to better because I could see and respond faster (like moving around in battlefield 1 - scanning for an enemy hiding somewhere or running in peripheral vision)
- the controls to navigate monitor settings is so much better with the joystick
- monitor design looks better imo

Cons of the PG258q to IPS 165hz
- bad resolution, everything is more blurry (not motion blur, just image quality in that sense) (native 1440p vs 1080p upscaled to 1440p is no competition, at least on these monitors).
- worse colours duh (having it side by side you can tell the extreme difference)
- smaller screen - found it a lot harder to see enemies heads after coming from 27" 1440p (of course I got used to it after a couple weeks)
- asus pg258q seems to have problem with the sound not working (or something is wrong with my system - but many others have reported similar issues in regards to ASUS built in speakers. I don't use them, but still, it's part of the monitor I've paid for)
- increased input lag - slightly but noticeable, especially during the actual aiming/recoil control. Now, against most average/okay players in the FPS game, it didn't matter much, I'd still win the gunfight but I certainly felt it wasn't as connected and responsive, and I'd miss a few more headshots that I would have sworn 100% that it was a sure kill. HOWEVER, when it was against a really good player at my level and higher, that's where I felt it the most. I'd find the input lag disadvantage much more noticeable and instances of "what the f, I know I headshot that guy, I know I shot him first, he should be dead I know this" happened a lot more against those same players (had to luxury to play against some of these players over the months).

So I reverted back to my IPS 165hz, and boom, I could instantly feel the difference. Those shots that I sworn I could have had, registered, the recoil was more controlled.

I also performed maybe 5-10 minutes each time I played (maybe 5-6 days a week), comparisons of button to pixel delays in battlefield 1 by shooting guns, and observing how long itd take to register on screen (yes I know there's margin of error, but when you've played FPS for that long, you notice things) and switching monitors of repeating this. I also did left to right movements, where I'd move and wait for screen to register the movement and immediately move the opposite direction and this once again showed the TN 240hz had more input lag. I also used my friends PG279q on many occasions and noticed very similar things, (the PG279q is actually even faster than my XG2703-GS).

Ultimately, my gaming performance is still very good (I regularly get top score in battlefield 1 in a 64 player map - this is not bragging, but just emphasising the increased input lag isn't really that bad), however in the competitive scene (CS GO or really good aimers), I often struggle more. Of course, TFTcentral showed the processing lag to be higher at 2.9ms for the PG258Q TN 240hz, but I was stupid and didn't understand that at THAT time prior to purchase.

I'm now going to sell the PG258q at a loss, because overall, I play better with the IPS 165hz and get more enjoyment from the higher resolution, colours, viewing angles, despite the higher motion blur. I will be relying more on TFTcentral in the future on the signal processing portion (I know PCmonitor info combines signal + pixel response, however they don't separate it so that is annoying, because if they did I could compare results against TFTcentral).

[Chief Blur Buster]

Thanks for reporting your findings!

[StrobeMaster]

Hello,
Just wanted to share my personal experience on this matter as I have:
...

Thanks for sharing - made me change my mind.
If I compare the numbers of the 240Hz/TN (RG258Q) and the 165Hz/AHVA=IPS (PG279Q) on tft-central, I come to the conclusion that both monitors should be on par regarding button-to-screen input lag. Apparently, GSYNC sweeps off the advantage the 240Hz/TN should have in theory, although the advantage would be surprisingly small anyway - something like 2ms. So why does the 165Hz/IPS still appear to be faster? I think it's simply because the better image quality makes it easier and thereby also faster for the visual system to process the images. In a way, this is trivial. A low-resolution and low-contrast image is just harder to "read", which makes the reading also slower. But I would never have guessed that the difference in image quality between these monitors is sufficient for having an impact on FPS gaming performance. Very interesting! Unfortunately, the monitors are different in so many aspects (size, pixel resolution, contrast, color, viewing angles) that we cannot really tell which of these aspects have how much impact on perceived input lag. Motion blur, at least, appears to be less crucial in comparison. Anyway, the take-home message here seems to be: nicer=faster. So even FPS gamers should think twice when sacrificing image quality for seemingly better monitor timing.

[RealNC]

Hello,
Just wanted to share my personal experience on this matter as I have:
...

Thanks for sharing - made me change my mind.

I'm not known as a proponent of the 1st gen 240Hz panels (a bit of the opposite, in fact; it seems to me they've been rushed to market in a somewhat half-baked state.) But I do have my reservations when it comes to people thinking they are noticeably affected by a 2ms or 3ms latency difference. There's other factors to consider. Screen size, resolution, and image quality can affect aiming.

If the differences are indeed down to a 3ms latency difference, then you should get the same results by using the same monitor but introducing an artificial 3ms penalty. If you then don't get the same results (and I doubt you will), then it's not the latency differences of the monitors to blame. I'm not sure how one could set up such a test though, and do so using an ABX method (where you don't know whether you currently are using a 3ms disadvantage or not.)

[StrobeMaster]

If the differences are indeed down to a 3ms latency difference, then you should get the same results by using the same monitor but introducing an artificial 3ms penalty. If you then don't get the same results (and I doubt you will), then it's not the latency differences of the monitors to blame. I'm not sure how one could set up such a test though, and do so using an ABX method (where you don't know whether you currently are using a 3ms disadvantage or not.)

Hmm. How tolerant are VT-tweakable 240Hz monitors regarding vertical front/back porch?

[KKNDT]

"Lag competition between 240HZ TN and 165HZ IPS" is a very hot topic around me. However my knowledge is insufficient to asnwer it.That's why I open this thread here. Till now most people I know do trust TFTcentral's result. I believe 240HZ TN is sure to win regarding lag randomness factor explaned here. But who wins on absolute lag? I still can't find a authoritative saying whose data is more reliable?

RTINGS: XL2540 3.7MS VS XB271HU 4.6MS
TFTCENTRAL: PG258Q 4.6MS VS PG279Q 3.25MS, SMTT 2
TOM'S HARDWARE: PG258Q 20MS VS XG2703-GS 31MS

As far as I can conclude, display-only lag is affected by:

1. Signal processing lag (scaling/buffering... etc.)
2. Scanout lag
3. GTG
4. maybe something missed

The 1st section is a black box to me at the moment. And I always want to know: Is panel itself a lag factor?( I'm not talking about GTG. I guess maybe it takes some time to "drive" a specified panel?)

One example here:
The popular DELL U2717D (with PLS panel) has aweful input lag(25MS+ by TFTcentral). But I have heart some batches of this model use LG AH-IPS panel which perfoms much better, maybe similar with U2715H(12MS by TFTcentral).