UHD630 - 4K screen flicker with HDMI (only during XTU stress test). No issues through usb-c. What's going on ?

[LGbr3]

Hi,

I am having many issues with my 27uk850-W monitor. I hope you can help me get some answers. 

My setup : Dell XPS 9570 / i7 (i7-8750H CPU / intel UHD 630) / 16Gig ram / 4K in built screen + LG 27UK850.

The issues : 

1. Whenever the monitor is connected by HDMI, and the laptop is under CPU load under a stress test (for example XTU), the screen starts flickering on and off. Sometimes the screen disappears completely (becomes gray or black). The extended display is still visible at this point. When the monitor is connected through USB-C, this problems does NOT occur and everything is fine (even under heavy, heavy load). I have a high-speed HDMI cable that supports 4K-5K - https://www.coolblue.nl/en/product/154321/veripart-hdmi-cable-gold-plated-1-5-meters.html.  When I connect my laptop to the TV (not 4K) then there is no problem through HDMI.

2. Sometimes, connecting through USB-C with the cable that came with the monitor works perfectly, but sometimes I get the message ' display port may be limited ' ... then for some reason it works again. This is very strange since there were no updates. That's when I switched to HDMI and found out about problem number 1.

3. I have a TB3 port on the XPS and recently bought this cable: https://www.amazon.de/CHOETECH-Zertifiziert-Thunderbolt-Kompatibel-kompatibel/dp/B074DTBN1B/ref=mp_s_a_1_3?keywords=thunderbolt+3+40gbps&qid=1568266060&s=gateway&sprefix=thunderbolt+3+40&sr=8-3  ... When I attach it to the monitor it does not work. There is no picture. Which USB-C type cable do I need ?>

By now I am getting super frustrated with the monitor. What I would actually just want is to be able to plug in an HDMI cable and have no issues under CPU load. 

Do you have any idea what the solution is to my issues? Why does the HDMI connection become unstable when the CPU comes under load? Also, why does that problem not happen when I use the USB-C cable? ALso, why does a TB3 cable not work with the monitor (is a TB3 cable not backward compatible?). 

Thanks,

Lex 

[n_scott_pearson]

My guess? They have a VRM that is monitoring regulator temperature and, if they go over a certain threshold, is hard-asserting PROCHOT.

...S

[LGbr3]

I'm thinking something along those lines as well. Might also be bios related as they pushed out a bios update last week which 'solves thermal issues'. Of course it doesn't solve anything, but when the mean 'solving' they probably are lowering thresholds in order to reduce heat even more. This could be something. Might try a bios downgrade as well. Anyway .. thank you for all your replies.. If something comes to mind I'd be thankful to hear about it.

Though this is interesting too : I lowered the max clock speed from 3,9 Ghz to 3,2Ghz in throttlestop. ... and it's still happening. Temps are lower then and the problem persists. Does not make sense.

[n_scott_pearson]

I would check the BIOS parameters to see if any are new/related.

...S

[Esteban_C_Intel]

Hello LGbr3,

I also don't want to interrupt the conversation here but I have more doubts and questions that actual solutions or workarounds. Before I ask my inquiries about this I would like to mention that all the questions and support given above by Al.Hill and n.scott.pearson are highly exceptional.

Now, my questions are the following:

1- When the flicker occurs, does the iGPU or Intel® graphics controller usage is at full load?

2- Does this only occur while using 4K at 60Hz?

3- Have you tried 4K at 59Hz or 30Hz? If so, what was the outcome?

4- By any chance do you know what is the TDP of the package when the problem occur?

5- Is there any way you can record a video with the stress tests you wish while the task manager is open so we can see the CPU, GPU usage? And to watch the issue.

Esteban Ch.

Intel Customer Support Technician

A Contingent Worker at Intel

[LGbr3]

Hi Esteban,

Not interrupting at all. Thank you for replying. I appreciate it.

1. It happens when the CPU is stressed to max load. Then the laptop freezes as well. After a minute or 2 the picture comes back (after the freez is over). It happens only on HDMI. On usb-c the CPU can be stressed to max forever with no problem happening.
2. It seems so. The problem does not occur on FHD when the CPU is under full load. I don't have another 4K screen to test it on, but for now it seems it's only on 4K 60/59 Hz. Because it works on FHD, Dell tells me that it's not their problem. Imagine that. LG has not come back to me. They seem to not even read emails.
3. I tried 60 and 59 (both are actually the same). I will have a try at 30 in order to see what happens tomorrow morning.
4. That would be at around 40W, but I have to check that to be sure. I will set up the monitor as extended and put the stress test on the monitor screen in order to be able to see that hopefully.
5. I will record it tomorrow morning and post the shareable link to google drive here in my next reply.

Thanks again.,

Lex

[LGbr3]

Hi,

So here are some videos of what's happening, as I promised. On 30Hz there is no issue. On 60Hz see the video's below :

HDMI to 4K screen : https://drive.google.com/open?id=16R4I9bXZWqbS0D_3BGnWPyov0WxYfgro

USB-C to 4K screen : https://drive.google.com/open?id=16aTSyE268RkeJURpc6dyLosDGCwzGLG0

Anyone have an idea ?

Lex

[Esteban_C_Intel]

Hello LGbr3,

Thank you for the information and videos provided, all of it helps me to understand what might be the cause of the issue.

In this case, I would like you to try to do the following:

1. Search on your OEM website to see if there is any LSPCON Firmware update, if so please update it.

2. Check on your laptop's website to see if there's any BIOS update available.

3. Please try with the Microsoft Basic Display Adapter (uninstall all the Intel® or DELL™ graphics driver) and let me know if the issue persists. Also, make sure you use the 4K resolution and the 59 or 60Hz refresh rate.

Let me know the outcome.

Esteban Ch.

Intel Customer Support Technician

A Contingent Worker at Intel

[LGbr3]

Hey Esteban,

Thanks again ... to answer the points ..

1. None of the sort is available. Can't find anything LSPCon related in relation to Dell Firmware, or even drivers.
2. I have the latest BIOS .
3. Basic Display Adapter won't even let me find a second screen. It's only working for the built in display (which does not give issues) By the way, the internal display is also 4K *(the laptop screen)

Greets,

Lex

[Wanner_G_Intel]

Hello LGbr3,

Thank you for your response.

We will do further research and get back to you soon.

Wanner G.

Intel Customer Support Technician

A Contingent Worker at Intel

[LGbr3]

Hi Wanner,

Thank you for your response. I appreciate it a lot.

Have a good day,

Lex

[Esteban_C_Intel]

Hello LGbr3,

After deep research and after trying to replicate this issue on our labs (unsuccessfully since we could not replicate it), I would like to inform you that this issue should be related with either a hardware issue (HDMI® port or LSPCON) or a compatibility issue between the TV and the laptop. In this case, our best recommendation for you is to get in contact with your OEM so they can further assist you with this issue.

Esteban Ch. 

Intel Customer Support Technician

A Contingent Worker at Intel

[LGbr3]

Hi Esteban,

Thank you. I really appreciate the effort that you, and others have put into it. I've contacted Dell and LG and Dell doesn't want to help cause the warranty is 1 month over date. LG on the other hand blames Dell. One last question though: do you think that bios firmware can have any influence on this ? Also, is it possible that laptop and monitor are not compatible, even if the specs say they are ?

** note : I've tried the HDMI again this morning and I got it to work. However it only worked 1 time. After a restart, I had the same problem.

Lex

[LGbr3]

Update : For no reason and without any warning, USB-C stopped working as well ... it now says ' display port may be limited ' ... All I did was go to sleep at night and start the laptop in the morning.

[LGbr3 · Accepted solution]

UPDATE : SOLVED

I down graded from BIOS 1.13 to 1.10 and all my problems have gone away.

[AlHill]

A Dell bios issue. I am not surprised.

Glad you figured it out.

Doc

[LGbr3]

Guess what ... it was not because of using XTU

[AlHill]

I just said XTU was not supported on your processor.

Now, with all of the discovery that has been done here, I hope you make it clear to Dell that there is a problem with their bios, and demand a fix. It is good for you, and good for all the other Dell users out there. As I said initially, Dell is responsible for your laptop.

Again, I am glad you figured it out.

Doc

[LGbr3]

Whatever man. The issue is solved and who joins the conversation now, telling me what my next move must be ? Geez.

[AlHill]

You did all the work to solve this problem. If I were you, I would be very pleased that I solved the problem. I would also be a bit disappointed in Dell, and I would let them know that. If others have the same problem, how will they know where the solution is?

What you do is certainly your choice. And, said as a compliment, I am glad you figured it out.

Doc

[Esteban_C_Intel]

Hello LGbr3,

I'm glad you figure it out and glad to hear that the issue has been solved. 

In this case, it will be worth if you report these findings to Dell* so they can see there is a problem with their BIOS.

I would like to mention that maybe the BIOS update has a firmware or LSPCON update which has made the trick, anyway I'm glad is solved by now.

We will close this inquiry; but, if you need further assistance, please post a new question.

Esteban Ch.

Intel Customer Support Technician

A Contingent Worker at Intel

[LGbr3]

Hi Esteban,

Thank you for all your effort and the time you've put into replying and thinking of a solution. It's much appreciated.

I've actually involved Dell and LG from the start in this. But you know how it goes with 'support'. They never really gave me any tips except : switch cables, try the Dell drivers, and so on.

I've told them it's a bios problem, but their reaction was that they'd ask engineering 'which bios would provide stable performance'. Well, of course I don't need them for that.

I hope they do something with this, but I doubt it. As long as it's a few people having the issue they won't really care I am afraid ..

Lex