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asus vg279q - ELMB always has a double IMG

Posted: 12 May 2019, 03:39
by oof_oof
I got an asus vg279q earlier on this week.

things that seem to be working great:
-the colors are beautiful
-no back light bleed.. if there is it's very very slight in the bottom left corner.
-no dead pixels
-horizontal motion seems pretty good / acceptable. seems like it's how it should be


things that may not be working correctly:
-vertical motion seems way more blurry over horizontal. the https://www.testufo.com/frame rates-text vertical scrolling test really does not look like 144hz.. maybe closer to like 90hz or 100hz. .. even scrolling on facebook looks kinda bad and not like a 144hz vg248qz

-ELMB - no matter what I do I always get a very CLEAR double UFO img similar to if my frame rates were half of my HZ:
it kinda looks like this: https://i.imgur.com/AYVUoFU.png

i have tried with vsync on / off / freesync on and off in radeon control panel. I also even tried 2 differrent GPUs. both a rx 570 and a gtx 950.

I guess, what I am frustrated about is.. I really don't know if my monitor is defective or not.. and I would be pretty upset if I exchanged it for another one and got a different monitor with worse backlight bleed or dead pixels etc.

also another thing worth mentioning is. I also tried out an asus vg248qz .. and I kinda feel like that TN monitor had much better horizontal and vertical motion.. like the UFO on the normal test was super clear no matter what and I don't think i had any lightboost enabled on that when i tried it out. the example img of the 144hz ufo is kinda close to how my vg279q looks..

bonus info. before tying out the radeon video card.. i had no driver installed and tried out the frame skipping test.. and it only showed like 1/3rd the frames on 60hz .. it was weird.

I am pretty sure it's not frame skipping.. i took photos and stuff and they looked okay to me at 144hz.

i guess i am just confused because the monitor might be perfect // or it might be perfect with a ELMB problem or maybe even needs a firmware update.

Re: asus vg279q - ELMB always has a double IMG

Posted: 13 May 2019, 11:16
by RealNC
This is crosstalk. It's more pronounced on IPS panels due to slower pixel response times of IPS. All current IPS panels that support strobing have this issue. (Well, TN panels have it too, but it's less visible.)

Re: asus vg279q - ELMB always has a double IMG

Posted: 15 May 2019, 12:47
by Chief Blur Buster
See http://www.blurbusters.com/crosstalk

Quality varies a lot from monitor to monitor.

1. Find ways to do framerate=Hz
2. Lower your Hz ... less crosstalk with framerate=Hz at lower refresh rates
3. Choose TN instead of IPS for less crosstalk.
4. Faster pixel response GtG needed due to "cram the GtG elephant into the VBI" requirement of strobing, see high speed videos at www.blurbusters.com/scanout -- the faster the pixel response can be finished in the current refresh cycle, the easier it is to strobe at a higher quality -- like www.blurbusters.com/lightboost/video
5. Some monitors reduce crosstalk via a Large Vertical total -- a user hack that allows more time for GtG to settle between refresh cycles. BenQ/Zowie monitors do, but not sure about ASUS.

Re: asus vg279q - ELMB always has a double IMG

Posted: 16 May 2019, 11:00
by oof_oof
I returned the monitor to the store and bought another one of the exact same model and it has the exact same ELMB result.

1. how? the ufo test says 120 fps 120hz.
3. lol why have an ELMB option on a ips display then?

I contacted asus support and they want their techs to service the monitor lol.

i guess it's possible i got 2 in row that are faulty? the manufacter dates between the two were only 1 week off.

bonus info. the 1st monitor has much nicer REDs. (exact same monitor settings)

Re: asus vg279q - ELMB always has a double IMG

Posted: 16 May 2019, 12:36
by RealNC
oof_oof wrote:lol why have an ELMB option on a ips display then?
Because it's less noticeable when playing a game compared to a synthetic test that is especially designed to make crosstalk as visible as possible.

With that being said, IPS will have more MBR crosstalk than TN. That's just how it is. TN has crosstalk too, but less. IPS has more, and VA has even more.

Re: asus vg279q - ELMB always has a double IMG

Posted: 21 May 2019, 17:45
by Chief Blur Buster
TestUFO Crosstalk test is indeed intended to be synthetic, and is much less visible in actual games.

That said, well-engineered IPS/VA strobe backlights should have tolerable crosstalk (not as low as TN, but should not be totally awful). Sometimes you have to lower the Hz a bit (e.g. 100Hz or so) to reduce the strobe crosstalk. Also, the use of large vertical totals can help (see animation) if ASUS is one of the models that uses synchronous cable:panel scanout even during strobed modes. NVIDIA strobing (LightBoost/ULMB) use scanrate conversion in the scaler/TCON to create the large blanking intervals to hide the GtG elephant into the blanking interval -- you ideally want pixel response fast enough to be hidden in VBI. But sometimes other monitors can do it externally via Large Vertical Total -- like many 1080p 144Hz BenQ Zowie monitors.

Re: asus vg279q - ELMB always has a double IMG

Posted: 21 May 2019, 20:35
by Falkentyne
Chief Blur Buster wrote:TestUFO Crosstalk test is indeed intended to be synthetic, and is much less visible in actual games.

That said, well-engineered IPS/VA strobe backlights should have tolerable crosstalk (not as low as TN, but should not be totally awful). Sometimes you have to lower the Hz a bit (e.g. 100Hz or so) to reduce the strobe crosstalk. Also, the use of large vertical totals can help (see animation) if ASUS is one of the models that uses synchronous cable:panel scanout even during strobed modes. NVIDIA strobing (LightBoost/ULMB) use scanrate conversion in the scaler/TCON to create the large blanking intervals to hide the GtG elephant into the blanking interval -- you ideally want pixel response fast enough to be hidden in VBI. But sometimes other monitors can do it externally via Large Vertical Total -- like many 1080p 144Hz BenQ Zowie monitors.
Chief,
It could also be double strobing.
Crosstalk doesn't give a double image like that (unless it's at the top and bottom of the screen with the middle being nice and clear).
If it's strobing at double frequency (e.g. two strobe cycles every 6.9ms) then it will look like "two distinct UFO's".

OP needs to capture an accurate pursuit camera image for us to see it exactly.

Could be similar to those newer Benq/Zowie monitors that double strobe at 60hz and 85hz (Unfortunately).

Re: asus vg279q - ELMB always has a double IMG

Posted: 24 May 2019, 04:06
by oof_oof
Hi guys,

I can try making a video of my issue later today.

also it's worth noting that I bought another monitor of this exact same model 8 days ago and returned the other one and I have the exact same results on ELMB.

the differences in the 2 vg279q monitors are very slight and are as follows:
(exact same settings on both screens tested side by side)

monitor 1) has nicer reds and colors that pop more, watching videos with people their skin looks nicer.
monitor 2) trace free function seemed to be nicer on 0 - 60 .. where as the 1st monitor only looked good at 80.