Blur Busters Forums

Who you gonna call? The Blur Busters! For Everything Better Than 60Hz™ Skip to content

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

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!

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

Postby k2viper » 23 Jan 2018, 07:36

Hello guys,
Anyone using this new display yet?

http://www.lg.com/us/monitors/lg-27GK75 ... ng-monitor

Just ordered it, hope I'll get my hands on it on weekend or monday.
Picture on LG's off.site displays OSD: blur reduction simultaneously on with freesync. An error, probably?
I dont have an AMD graphics card to test freesync, anyway.

UPDATE Nov 2018: Settings for clearest 240Hz blur reduction mode on LG27GK750F-B monitor

Optimal/stable VT 1304 240hz resolution:

Image

It is an overclocked mode, but it is fully safe to use it. It may result in minor display instability: sometimes, depending on how often you open the OSD, display loses sync and goes blackscreen and back on. It may happen once a 2-3 days, may once a 2 weeks. The more you open OSD, the more often these black screens may occur. Easy fix: power cycle the monitor (via joystick button). After the powercycle, the new 2days-2weeks cycle begun. Only happens with high VT like 1300+.

Workaround for frameskipping bug/buffering out of order/stuttering-juddering:
In CRU under extension blocks find a 240hz resolution. By default its Actual Refresh rate is 239,759hz or 239,764hz or may be other number depending on your system, GPU, driver etc. You need to round it and get Actual refresh rate number exactly 239,760. Note that this refreshrate is also stated in user's manual. VT1304 resolution above is already 239,760.
You also may use lower values like 1182-1184 (only 2-4 above default 1180), the point is to get exact 239,760 if it is not exact at defaults.

Service menu: viewtopic.php?f=2&t=4422 , no useful options found though.

"Optimal" settings: I stick with Gamma mode 4, default contrast and black equalizer, 45 brightness, Fast overdrive, MBR on full-time (yes I love blur reduction and CRT-like look!). Personally I found default colors fine enough, but R-G-B are also tweakable.

ICC profile is installed with display INF: http://gscs-b2c.lge.com/downloadFile?fi ... iLocE7WGOw
How to enable ICC profile: http://www.tftcentral.co.uk/articles/ic ... tm#install

Presets: Gamer 1 and Gamer 2 are the only usable profiles, they are fully adjustable. It's not recommended to use any other presets like FPS/RTS etc.

For minimal input lag make sure you choose "Original" scaling mode under Aspect ratio settings. Default is Full wide, and it is like ~1full frame slower then Original! So if you dont absolutely have to, always choose Original mode!
There is no advertised "Dynamic action sync" option found, but in Original mode this display goes on par with best other 240hz screens with 4,5-5,0ms of total input delay

Freesync and Motion blur reduction dont work together, and I have an Nvidia card, so no Freesync experience to share here.
Last edited by k2viper on 06 Feb 2018, 09:33, edited 1 time in total.
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

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

Postby RealNC » 23 Jan 2018, 09:09

k2viper wrote:Picture on LG's off.site displays OSD: blur reduction simultaneously on with freesync. An error, probably?

That's just a photoshop for marketing purposes. Misleading, but the person doing it had probably no idea what this stuff even means :P
TwitterSteamGitHubStack Overflow
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.
User avatar
RealNC
 
Posts: 2775
Joined: 24 Dec 2013, 18:32

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

Postby k2viper » 23 Jan 2018, 09:14

User's manual clearly states that Freesync and 1ms blur reduction cannot be used at the same time. Predictable :)

I found a review of this display, looks like it has low input lag, fast response times and very low overshoot, so with strobing it should be fine at 240Hz.

https://be.hardware.info/reviews/7841/2 ... g-27gk750f (use google translate to read)

Currently I own Asus VG278H and I use it with constant lightboost 10% enabled, so I'm pretty used to blur reduction (strobing).
Just wanted to get a 240hz display not smaller then my current 27, but I didnt want to sacrifice blur reduction, thats why I skipped first 27" 240hz displays, such as Acer XB272.

Cant wait to test this LG, actually.
Ordered it in Russia for ~480USD, even cheaper then recommended price on LG's site. Very good price imo.

ps. Btw, is there a way to use VRR (Freesync) having Nvidia graphics card (i have 1070)?
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

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

Postby RealNC » 23 Jan 2018, 09:39

k2viper wrote:ps. Btw, is there a way to use VRR (Freesync) having Nvidia graphics card (i have 1070)?

Nope. NVidia refuses to support freesync. And there's no workarounds or hacks for this.
TwitterSteamGitHubStack Overflow
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.
User avatar
RealNC
 
Posts: 2775
Joined: 24 Dec 2013, 18:32

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

Postby open » 25 Jan 2018, 02:05

You will still see an increase in smoothness. Higher refresh rates even without g-sync or vsync or freesinc will still have more smoothness. The length of each refresh is the maximum ammount of time that the refresh cycle can add delay to any part of a frame.

Bonus question: Is this the only monitor besides the benqs that can do strobing at 240hz?
open
 
Posts: 223
Joined: 02 Jul 2017, 20:46

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

Postby k2viper » 25 Jan 2018, 06:40

open wrote:You will still see an increase in smoothness. Higher refresh rates even without g-sync or vsync or freesinc will still have more smoothness. The length of each refresh is the maximum ammount of time that the refresh cycle can add delay to any part of a frame.


I'm sure that I will definitely feel difference between my old "1st-gen" VG278H and modern, more responsive panel with twice more hertz.

open wrote:Bonus question: Is this the only monitor besides the benqs that can do strobing at 240hz?


Yes, and its the only 27" one that do so. Thats why I've been waiting for this model, and ordered it right as they become available.

Btw, I'm still looking for a method to get service menu on LG displays with joystick (no dedicated "power" and "menu" buttons available).
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

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

Postby k2viper » 30 Jan 2018, 08:54

Finally got my monitor, gonna try it tonight.

https://youtu.be/gKtZLw0AksM?t=385

It definitely strobes at 240hz.
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

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

Postby k2viper » 30 Jan 2018, 12:52

Got display up and running!

Very well built, strong aluminium stand w/tilt, accessory package (includes PSU, 3 cables - DP, HDMI and USB3).

First impressions - 240Hz is great, clear, much fluidy and smooth then 120hz. Input lag is lower comparing to VG278H, I directly feel how responsive this display is.

Strobe crosstalk is more visible then on my VG278H 120hz lightboost 10%, but maybe panel needs more warming up, after 30min usage it crosstalks less then right after "cold boot".
On 144hz and 120hz crosstalk is present too. I will experiment with VT tweaks soon.

What i feel almost perfect, is the overdrive, it's fast and almost NO visible overshoot, even scrolling text in browser seems very readable. I'm pretty impressed.

I took some pictures, but I think you dont want to look at standard package and display body pics, but crosstalk shots I took look very smeared, I need to try different camera or camera settings.
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

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

Postby Chief Blur Buster » 30 Jan 2018, 13:07

k2viper wrote:Strobe crosstalk is more visible then on my VG278H 120hz lightboost 10%, but maybe panel needs more warming up, after 30min usage it crosstalks less then right after "cold boot".
On 144hz and 120hz crosstalk is present too. I will experiment with VT tweaks soon.

Please do.

Follow Appendix A of www.blurbusters.com/crosstalk for creating working custom vertical totals from an existing mode. (Basically in ToastyX CRU, copying the 240Hz mode, locking the Pixel Clock, then increasing the Vertical Total in order to force the refresh rate to go down while maintaining Pixel Clock). 240Hz gives you about 4ms of VBI time at 120Hz+Large VBI. If strobe crosstalk is more intense at top or bottom, try transferring pixels between Vertical Front Porch and Vertical Back Porch. This may force the monitor to bring the strobe pulse earlier/later, shifting the crosstalk zone upwards/downwards. Different monitors have different strobing behaviours.

k2viper wrote:I took some pictures, but I think you dont want to look at standard package and display body pics, but crosstalk shots I took look very smeared, I need to try different camera or camera settings.

Usually, you need to use a pursuit camera technique to successfully capture WYSIWYG motion blur photography. Formerly the domain of scientific laboratories, I'm the creator of the simplified/inexpensive blogger-friendly pursuit camera technique now used by others (e.g. RTINGS, TFTCentral, pcmonitors, etc).

However, for strobe backlights since it's a near-instantaneous-flash, it's possible to analyze strobe crosstalk via a stationary photograph. Point your smartphone at screen, adjust exposure exactly, then snap. Simply make your camera exposure no more than one refresh cycle (e.g. 1/240sec or faster for 240Hz), use a 3rd party camera app to give your smartphone manual exposure adjustment.

That said, top, center, and bottom can have different amounts of strobe crosstalk -- this is because the pixels are refreshed at different times during a refresh cycle (top to bottom scanout) -- before the global backlight flash of a blur-reducing strobe backlight. As a result, crosstalk can be different due to differing levels of incomplete LCD GtG pixel transitions at the time of the visible flash. We have found ways to adjust/reduce this via strobe phase, length, and Large Vertical Totals, explained in Advanced Crosstalk FAQ -- but it only works as long as the monitor co-operates.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors
User avatar
Chief Blur Buster
Site Admin
 
Posts: 6374
Joined: 05 Dec 2013, 15:44

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

Postby k2viper » 30 Jan 2018, 13:14

Quick custom res test through nvidia CP - supports pixelclock up to ~640Mhz!
Afair Benqs worked only up to 600mhz.
Crosstalk reduced.

But maybe you guys advise me to adopt custom res to reduce crosstalk even more?

Image
User avatar
k2viper
 
Posts: 288
Joined: 23 Jan 2018, 06:30

Next

Return to General — Displays, Graphics & More

Who is online

Users browsing this forum: No registered users and 12 guests