Need help checking my DisplayPort version

[e22big]

I recently bought a new monitor, LG 32UK550 (because I was an idiot and dropped my old 27UL600), the store - as well as my LG official website listed this display as having a DisplayPort 1.4, however it was DisplayPort 1.2 in basically every LG official website. The store I purchased it from assure me that it got DisplayPort 1.4 - and I did make sure that I can configure it to 10 bit, 4k, 60hz with no chromasubsampling without any issue before I purchased it. 

 

However, despite, setting it to 10 bit, I saw colour banding in quite a few instances (Spotify app, some game, gradient blue area etc.) which is something I've never noticed before on my old 27UL600 display. Is there a way to make sure that my monitor does indeed has DP 1.4? It has been just a couple of days since I bought it so I probably be able to return this monitor had something been wrong with the spec it was advertised for. 

 

Summary of the situation

- This display is advertised locally as having DP 1.4

- I did make sure that it can run in 10-bit, 4k 60 hz, full RGB range

- It got quite a bit of banding, especially in gradient scene, app like Spotify looks so bad especially when you don't sit directly in front of the monitor

[e22big]

[Exidor]

Try this test first

https://www.rtings.com/tv/learn/chroma-subsampling

 

[e22big]

8 hours ago, Exidor said:

Try this test first

https://www.rtings.com/tv/learn/chroma-subsampling

 

I did try lower colur to 8-bit or run the monitor at 30hz and still saw bandint, not sure if chromasubsampling test would help

[Exidor]

Well the only way I know to see what mode the display is in is to use the displays diagnostic menu.

Should be somewhere in the manual.

 

Banding is usually not tied to DP it is usually tied to compression.

Does it state that the monitor uses some sort of DP compression?

[e22big]

11 hours ago, Exidor said:

Well the only way I know to see what mode the display is in is to use the displays diagnostic menu.

Should be somewhere in the manual.

 

Banding is usually not tied to DP it is usually tied to compression.

Does it state that the monitor uses some sort of DP compression?

hmnn gotta look into it but I don't think so but you've never know

 

I had suspected that the monitor run on DP 1.2 but use display stream compression to make it accepts 4k 60fps full RGB signal, if that's the case it seem to fit your theory perfectly

[Glenwing]

Both DP 1.2 and DP 1.4 can support 4K 60 Hz 10 bpc RGB, so it's really a moot point.

[Exidor]

Could be that the panel runs internally at 8bit and is not a true 10bit panel that would also lead to colorbanding.

Try running it in 8bit mode.

[e22big]

8 hours ago, Glenwing said:

Both DP 1.2 and DP 1.4 can support 4K 60 Hz 10 bpc RGB, so it's really a moot point.

really? my understanding that DP 1.2 support 4k 30fps 10bpc RGB (at 21 gbps)

[Glenwing]

1 hour ago, e22big said:

really? my understanding that DP 1.2 support 4k 30fps 10bpc RGB (at 21 gbps)

No; 4K 60 Hz 8 bpc RGB is supported by HDMI 2.0, and DisplayPort 1.2 has 20% more bandwidth than HDMI 2.0 which is enough to support 10 bpc color depth in addition.

[e22big]

1 hour ago, Glenwing said:

No; 4K 60 Hz 8 bpc RGB is supported by HDMI 2.0, and DisplayPort 1.2 has 20% more bandwidth than HDMI 2.0 which is enough to support 10 bpc color depth in addition.

I see, too bad, had I know that I would have go with the Dell S2721QS.

 

In that case what's the DP 1.4 advantage over 1.2 in a typical resolution (40k 60hz or 1440p 144hz 10 bpc)?

[e22big]

Turn out I might have a defect model here, went to the shop I bought it from and it never show any banding issue (or at least not this bad) as far as as Spotify goes

 

Might try installing driver and if that doesn't help I'll probably RMA it

[Glenwing]

1 hour ago, e22big said:

I see, too bad, had I know that I would have go with the Dell S2721QS.

 

In that case what's the DP 1.4 advantage over 1.2 in a typical resolution (40k 60hz or 1440p 144hz 10 bpc)?

For 4K, none, though some manufacturers may label them "DP 1.4" if they support HDR, they will be implemented with HBR2 bandwidth though. For 1440p 144 Hz, DP 1.4 is required to use at 10 bpc color depth, as DP 1.2 will only support 8 bpc at 1440p 144 Hz.

[e22big]

On 1/1/2021 at 7:08 PM, Glenwing said:

For 4K, none, though some manufacturers may label them "DP 1.4" if they support HDR, they will be implemented with HBR2 bandwidth though. For 1440p 144 Hz, DP 1.4 is required to use at 10 bpc color depth, as DP 1.2 will only support 8 bpc at 1440p 144 Hz.

I just find out today that the colour banding is not my monitor issue - brought it to the shop, they plug it in their computer and the issue just goes away

 

do you have any idea what other area I should look into to find the cause of banding? it's not my driver, DDU it and reinstall driver doesn't help, it shouldn't be my GPU since it's a brand new 3080, don't know where to look now

 

[Glenwing]

4 hours ago, e22big said:

I just find out today that the colour banding is not my monitor issue - brought it to the shop, they plug it in their computer and the issue just goes away

 

do you have any idea what other area I should look into to find the cause of banding? it's not my driver, DDU it and reinstall driver doesn't help, it shouldn't be my GPU since it's a brand new 3080, don't know where to look now

 

Probably just the way the monitor is calibrated. Have you tried different settings on the monitor, or just been using the defaults?

[e22big]

7 hours ago, Glenwing said:

Probably just the way the monitor is calibrated. Have you tried different settings on the monitor, or just been using the defaults?

I tried calibrating it for quite a few time already, some picture mode shows less banding but only because they crank gamma up so much that everything looks wash out

 

I am planning to have some professional calibrator try their hands on but the monitor in the shop I tried can archieve this without having to cranking gamma point in anyway