LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

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Chief Blur Buster
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by Chief Blur Buster » 21 Oct 2018, 11:44

k2viper wrote:Some measurements on this monitor did by XAKE, and he told me that impact of MBR on input latency was 0-2ms, minimal to no impact in his tests. Also, Original aspect mode decreases input delay regardless if MBR is on or off.
The specifics get a bit complicated, but since I have been strobe-tuning monitors for a few years now, for multiple manufacturers... Some of you are very familiar with my Blur Busters Strobe Utility which provides end-user strobe tuning for BenQ Zowie monitors.

2ms is normal latency penalty for 240Hz strobing since strobing is a latency gradient throughout the vertical dimension of the screen surface.

The latency gradient asymmetry effect occurs because of the top-to-bottom refresh scanout of panel in dark (LCD panel tech) versus the all-at-once global strobe flash (backlight tech).

Look at the high speed video of LightBoost to understand how a screen-area-specific latency asymmetry effect can be created.

phpBB [video]


The position of the latency asymmetry depends on where the worst strobe crosstalk is -- horizontal band of of maximum number of copies of images at http://www.testufo.com/crosstalk

This is the 120Hz example. Divide all values by half for 240Hz.

Image

Image

So there is a location on the screen where latency penalty is practically 0ms and a location on the screen where latency penalty is 2ms, and so on... The latency penalty gradient ranges approximately from [0ms ..... (refresh cycle duration minus strobe length duration)]. Most of the time, a strobe backlight flashes for about 1ms on most newer screens (1ms MPRT). Most of the time the flash is a tiny part of a refresh cycle, so it's more effectively [0ms...refresh cycle duration]. When you average it out, it's half a refresh cycle duration. So 120Hz strobing = half of 1/20sec = an average of approximately 4ms lag penalty for strobing.

That said, lag penalty for strobing can be worth it, when you consider HOWTO: Using ULMB Beautifully or Competitively ...

The blur reduction benefits can outweigh the latency penalty for specific kinds of gaming tactics that are very motion-intensive. It does not benefit stare-at-crosshair tactics as much, but it can help eye-tracking tactics (e.g. identifying camoflaged enemies during high speed helicoptor flyovers, or the fast-moving ball in Rocket League), amongst other things as demonstrated by the eye-tracking motion animations at www.testufo.com/eyetracking and www.testufo.com/persistence that reveals display quirks that only happen during eye tracking versus fixed-gaze. So there are certain games where blur reduction helps eSports, while it doesn't in other games, depending on your gameplay tactics.
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k2viper
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by k2viper » 22 Oct 2018, 06:17

TimeCompression, ericl
Yes, that bug may be not revision-dependant. I have contacts of owners who havent ever reported this issue. It may also be GPU dependant, as I found that actual default 240hz timings and exact refreshrate are not fully equal on Nvidia and AMD cards.
Anyway, good as it seems my fix's working for those who experience this bug. Personally I havent seen that bug for a whole time since February when I put up my VT1304 custom resolution as main.
Chief Blur Buster wrote: That said, lag penalty for strobing can be worth it, when you consider HOWTO: Using ULMB Beautifully or Competitively ...

The blur reduction benefits can outweigh the latency penalty for specific kinds of gaming tactics that are very motion-intensive. It does not benefit stare-at-crosshair tactics as much, but it can help eye-tracking tactics (e.g. identifying camoflaged enemies during high speed helicoptor flyovers, or the fast-moving ball in Rocket League), amongst other things as demonstrated by the eye-tracking motion animations at www.testufo.com/eyetracking and www.testufo.com/persistence that reveals display quirks that only happen during eye tracking versus fixed-gaze. So there are certain games where blur reduction helps eSports, while it doesn't in other games, depending on your gameplay tactics.
Yes Chief, absolutely. It also worth noting that higher are the refreshrates and strobe rates, the less is the strobing penalty.
As a shooter player (overwatch, formerely TF2 and other class-based), I confirm that blur reduction massively helps in tracking aiming tecnhiques. Overwatch Soldier/Tracer/Zarya primary attacks, I even tend to track when bursting close range targets with Hanzo "E" and landing a headshot to a flashbanged Genji, there are many scenarios when I feel that blur reduction clears my targets' edges and look, and I can track them more accurate.

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by 1q3er5 » 02 Nov 2018, 03:45

Hi all, this monitor is on sale for 300 bucks Canadian. I don't have time to read through 33 pages, but I play Cs-go competitively - is this monitor a yay or a nay?????? I would like to run it at 240 Hz - should I get it or are there issues like input lag etc. that I should be weary of.

Thanks in advance.

ericl
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by ericl » 02 Nov 2018, 09:53

$300? Where?!

And yes, it's good. I do comp Overwatch & CS:GO.

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by 1q3er5 » 02 Nov 2018, 22:16

ericl wrote:$300? Where?!

And yes, it's good. I do comp Overwatch & CS:GO.


Sigh it's gone now ... it was listed over at /r/bapcsalescanada/ it's back up to 480 canadian ... damn which I had a definitive answer sooner ... woulda bought it lol. That's what I hate about these huge threads

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by A Solid lad » 03 Nov 2018, 06:36

Well... if you'd have read thru the huge thread, you'd see how much I hate this monitor at this point.
How I see it: It's a high input lag monitor, which also has hazy looking, distracting motion compared to good 240hz monitors like the AW2518Hf and XL2740.
There's many people on this forum, praising it, but I strongly disagree with them after testning other 240hz screens. (See my signature.)

*EDIT: I even passed on this LG when it was on sale for 250 eur here, where I live. The AW2518Hf is a much, much better buy at 300 eur.
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Monitors I've used/use: IBM p275, Benq XL2411Z, Alienware AW2518Hf, Alienware AW2518H, Acer XF270HA, LG 27GK750F-B, Benq XL2740, ACER XB271HU, ACER XG270HUa, Benq XL2720Z, Benq XL2540

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by k2viper » 03 Nov 2018, 13:38

A Solid lad wrote:How I see it: It's a high input lag monitor
This is already fixed in Original scaling mode.
Who praise it? I just use it, not praise. But many people at this point are sure that it definitely cost its money.

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by A Solid lad » 03 Nov 2018, 20:39

k2viper wrote:
A Solid lad wrote:How I see it: It's a high input lag monitor
This is already fixed in Original scaling mode.
Who praise it? I just use it, not praise. But many people at this point are sure that it definitely cost its money.
I'm sorry, I didn't mean you... I remember some people who never tried other 240hz screens touting it as the best one... always manages to infuriate me, when someone calls something "the best" without trying any of it's alternatives, or having the skills necessary to distinguish between good and excellent...
As for original scaling mode... I haven't tried it :/
But even if the monitor equals the alienware and Benq in terms of input lag when using it, you're still left with more hazy motion compared to the xl2740 in both strobed and non-strobed operation...
I'd LOVE it, if the LG could somehow become great...because it's price is constantly at 350 eur in my country, and the xl2740 is usually 580 eur (atm one shop sells 1 unit for 480), but it's not...
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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by k2viper » 04 Nov 2018, 05:25

A Solid lad wrote:I remember some people who never tried other 240hz screens touting it as the best one... always manages to infuriate me, when someone calls something "the best" without trying any of it's alternatives, or having the skills necessary to distinguish between good and excellent...
Calm down, a fact that you managed to try some number of 240hz screens, itself doesnt make you having more skills to distinguish between good and excellent. Tbh, the difference you claiming, is your personal subjective feeling/pov. That doesnt neccessarily means that there is no such difference, but it means people may doubt about it, and doubt that it's such huge.

Not trying to insult you, just sober look at the things.

Btw you remember me and you trying Latencymon DPC measurements with this LG? With Original scaling mode, idle DPC level also went down, its often below 20us (previously high 20s-low 30s), and I started to see one-digit latency numbers.
A Solid lad wrote: I'd LOVE it, if the LG could somehow become great...because it's price is constantly at 350 eur in my country, and the xl2740 is usually 580 eur (atm one shop sells 1 unit for 480), but it's not...
Yes, price is a factor, in Russia XL2740 costs ~250usd more, almost twice the LG's price. And I, as many other people, not sure is XL2740 that much better overall for such premium. I currently dont see a point to switch from LG, unless newer "0,5ms" monitors will be released, I expect them in mid-late 2019.

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Re: LG 27GK750F-B - 240Hz, 27" 1ms Blur reduction, Freesync

Post by daniloberserk » 22 Nov 2018, 23:21

Just got this monitor today, it should be arriving next week or so. I really tried to extract some usefull information on this thread but it's so goddamn huge and there's a lot of anecdotal evidence going on so, if someone who have this display can just extract the good info (like VT tweaks, ICC profiles and configuration, best setups for a freesync setup or MBR, etc) I would REALLY appreciate! I'll try to do myself but my english really suck (I can read and understand quite easilly though so go figure).

This monitor is like 120USD cheaper then any other 240Hz display here on Brazil. I would love to get my hands on the XL2456 myself but I can't just pay the extra 315USD difference between this displays, so I really hope that I made a good decision in the end.

I saw some info about frames being buffered out of order (?) and frame skipping, this is a common thing? It's fixable?

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