Screen Flickering

minizv

minizv

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I run WIN7 with 16GB RAM and an Intel i7 chip. I have an LG 40" 4k screen/TV mated to an Asus R7 370 Series (Strix) 4GB graphics card. Most of the time the screen is steady but when working with programes with fine lines of text (Excel, Filezilla etc.) parts of these lines can, and often do, flicker. Very occasionally this flicker appears on the desktop and other places. Also, on a regular basis, long windows (Explorer etc.) that you scroll down will jump back to the beginning.

All drivers are up-to-date and I have experimented with various settings on the graphics card (which can be over-clocked but isn't). I have replaced the cable for what is probably the most expensive on the market! This is driving me nuts! Suggestions/solutions gratefully received.
 
Hi @minizv - that sounds like it could be two unrelated problems, but we'll try and get the flickering fixed first, as that must be pretty annoying for you!

There could be a lot of causes for this issue, so it would be helpful if we could narrow down some of the possibilities:
  • Do you have another monitor you could test, just to ensure it's not a problem there - I wonder if it's a problem related to using a 4k display. Windows 10 is pretty good at handling this, but there are some scaling problems in Windows 7.
  • Does it only happen to text? If so, have you tried playing with the ClearType settings?
  • Have you configured your display correctly? Particularly the refresh rate (does it make a difference when you try 30hz/50hz/60hz)? I suspect the problem may be related to this.
  • What resolution are you running on your 4k display? Does it still occur if you run something like 1080p?
  • Could you please try booting in to safe mode and see if the problem still occurs - this will rule out 3rd party extensions and some display driver/resolution issues.
 
Hi Ian, Many thanks for the reply. I have spent (yet another!) half day on this and unfortunately am no further ahead. I will reply to your questions one by one.
1 I originally upgraded to a Gigabyte 2GB card and a 32" 4k monitor. Unfortunately I had to run this at 2880x1530 as 3840x2160 made it too small to read and far too small to do the graphics work I spend most of my computer time on these days. However at both resolutions it performed perfectly. Both the monitor and card are now on my wife's machine (also WIN7) and running perfectly. The reason I do not use WIN10 is the terrible experience I had upgrading my (then) laptop from WIN7 - I never did get it to work and, 3x, had to reinstall WIN7! I did not dare to try to upgrade to WIN10 on my main machine. I now run WIN10 on my new laptop, as does my wife.
2 Yes, text only. Had a good play with Cleartype (didn't think of this myself), which was switched on, but the problem persists.
3 The screen will go to 70hz. It is running at 60hz, the maximum that Windows will let me run at. Previously I have tried all available refresh rates. The monitor is set at 32bit colour and I have tried it at 16bit but this makes no difference. It has a maximum resolution of 4096x2160 but the problem is the same at this resolution.
4 No it does not occur at 1080P but then the type is much larger. This flickering only happens with smaller lines of type. However, to my surprise, the jumping still occurs at this resolution. I suspect you may be correct in this being two problems.
5 In Safe Mode WIN7 will not let you run at greater resolution than 1080P so there is no way of telling if it would occur.
6 I checked again for software/firmware updates for the LG. There was a software update on 23rd December and I have applied this. Unfortunately this has not helped. The video card is automatically kept up-to-date.

Any more ideas?

Regards
David
 
Thanks for the detailed answers David :).

What happens if you try your existing setup with your wifes 32" 4k monitor? (with all of the rest of your setup the same)

I've done a bit of reading up on this and it looks like many other users are having the same problem :( - some have managed to fix it by dropping to 30hz (not a great solution, but useful to know).
 
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Hi Ian, I've had another good go at this. At one point I told Windows to update the video driver (I should know better!) and ended up with a 2006 VGA driver and 800x600 screen. It probably solved the problem.....
I then reinstalled the AMD video driver and it defauted to 30hz - it still flickers! Prior to this I hooked up my wife's 4k monitor and changed the resolution to 3840. It remained steady. I noticed that the Windows recommended resolution for this monitor is 3840. However on mine it is 1920, although higher resolutions are shown (there is no doubt that the screen is 4K!). The manual show it is capable of 3840 at 60hz. (I'm using a Monster cable and HDPC2.2 port by-the-way) Any further ideas and/or a solution to the jumping problem?

Regards

David
 
I'm out of ideas I'm afraid David, but I'll do some reading up over the weekend and see if I can find anything that may help :).
 
Hi David
I had similar issues with my 4k tv when I first got it - one of the main things that jumps out here is that even though your TV has HDMI 2.0, the graphics card you are using only uses HDMI 1.2, which can only run 4K resolution at 30hz. You'll need a gpu that has HDMI 2.0 and currently NVIDIA is the only option for this unless your tv has a Displayport input (in which case it will run 4k @ 60hz). The max resolution I could get out of my old graphics card was 2560x1440 @ 60hz. Anything more than this would be 30hz and cause the flickering you mention.
There's also a setting on many tv's themselves for overscanning, or scaling. Make sure yours is set to something like "monitor mode" or similar and that it uses a 1:1 pixel map (these settings should be in the tv's picture settings).
Another issue I had was that Win7 unfortunately was not built for resolutions higher than 1080p and the scaling is pretty terrible. To get the clearest picture I ended up using a newer NVIDIA gpu (GTX900 or later series with HDMI 2.0) and running Win 10 at 4K 60hz with Window's native scaling (I think it's in the "Make icons bigger/smaller bit").
Hope this helps somewhat!
 
Hi Ian / Naylor,

Thanks again for the replies. I have 'bit-the-bullet' and ordered a GTX1050 - hopefully both problems will disappear!

David
 
Let us know how it goes, David :). Good luck!
 
Hi Ian / Naylor,

Card arrived and duely installed. Software installation locked up! Manually installed. Runs at 3840 @ 60hz but I had 3 colour black text. Tried tweeking various settings (woked best with Cleartype turned off) but could not get rid of the multi-colour. Dropping to 30hz/RGB and adding back Cleartype has now given me a screen without random flickers on fine type.
However the 'jumping back to the begining' problem still occurs. I think that this only happens in Explorer - I do a lot of work in explorer so certainly notice it here. It is intermittent from about 2 minutes (rarely) to 20 minutes, averaging somewhere between 5 & 10. It occurs with text, icons or images on screen.

David
 
Hi Ian,

I hate to do this to you. The flickering problem has returned (with the new card). I had no problems yesterday with the new card installed. Overnight the machine was re-booted (presumably by Microsoft) and the problem is now as bad as ever! The ONLY changes made to the PC after installing the card was to tweek the colour management as the default setting gave a very orangey red. No flickering occured after this yesterday. I have tried various tweeks this morning using Cleartype and the Nvidia control panel but the flickering still occurs. I have also gone over my list of services/boot loads and got rid of some legacy ones that are no longer needed. I did this prior to your request to me on another thread so the machine has been re-booted since and it has made no difference.

David
 
Is everything still running at 30hz? I wonder if the graphics drivers updated via Windows Update and that changed some settings.

I'm all out of ideas on this part of the problem unfortunately, hopefully @Naylor will have some ideas as he's got 4k experience.

Could you be tempted to try an install of Windows 10? It would have much better compatibility with 4k displays. You could make an image backup of your drive so you can revert if it all goes wrong. As you've got a couple of problems, I'd strongly recommend a clean install of Windows 10 (you can still upgrade from W7 for free).
 
Hi Ian,

OK, I'm going to try for WIN10. Currently doing multiple Images of C: so cannot reply to you on the other thread. Friday 13th here - glad I'm not superstitious! Hopefully a successful change will cure both problems.

David
 
Hi Ian,

I upgraded to WIN10 - it did so flawlessly. At 3840x2160, 32bit, 30hz this problem remains - it is probably worse. However at 3840x2160, 32bit, 60hz, YCbCr420 (no choice for 444 or 442) the problem goes away. However at 60hz text in some programmes shows not as black but as red/black/blue. This occurs at both native text size (100%) and 125% - my preferred option as 100% is too small to read comfortably. I have tried 50hz and it makes no difference (the next choice down is 30hz). I cannot show you this colour split as screen captures show text as black (no it's not my eyes!).

David
 
I'm out of ideas or suggestions now unfortunately, however I did see @Naylor last night and he had some thoughts. I'll check with him and get more information :).
 
Hi David
Sorry to hear of your ongoing issues! There's a few more things to check here - are you using the dedicated 4K HDMI port on your monitor? Also have you uninstalled the old display drivers using DDU? http://www.guru3d.com/files-details/display-driver-uninstaller-download.html
After this, do a clean install of the NVIDIA drivers.
Does your TV have screen settings for "Monitor" mode or any overscan options? Sometimes these can really mess with the picture as TV's generally aren't used as monitors and they can have all sorts of factory display options on them that can ruin the image quality. Could you give us the exact model of your TV?
 
Hi Naylor,

Dedicated 4k port - yes. I have 2 and tried changing to the other one - same result.
Before running DDU I used Tweeking.com - Windows Repair to go over the sytem as it had been installed as an upgrade, rather than a clean install. Quite a number of issues were found but these were more under the heading of Housekeeping than correcting serious errors.
I then re-booted into Safe Mode and ran DDU twice. Once to remove any legacy AMD drivers then to uninstall the Nvidia drivers. After re-booting I installed the Nvidea drivers from the CD then updated them from Nvidia.
All of which had no effect at all! See image (I photographed the screen which does show up the problem).
LG model # 40UB800T - TB
Additional info that may be usefull. I said that this only occurs with some programmes. I thought that this might be the setting for "Let Nvidia control the color" or "let programmes control the color." Both show or don't show the same problem on individual programmes. I prefer the colour rendition in "let programmes control the color" so I will leave it this way unless you know better. Programmes I have tried and whether colour splitting occurs are as follows:
Firefox - yes (on menu bar)
PC Review web site - no
Gmail - no
Most other web sites - no. However I looked at one of my own sites: http://www.minisnz.com/ and the Home page show a small amount of clour split, nothing like as much as in the photo I am uploading. This works the same on-line and run locally. I am beginning to wonder whether the font might make a difference. Certainly bold fonts (of the same size) are not as bad as standard fonts. The splitting goes away with larger fonts, standard or bold. This can be seen by looking at a few pages on this web site. I looked at another of my sites, http://www.minibottlelibrary.com This uses, mainly, purple type on a cream background and no splitting is obvious, even on smaller sizes.
Explorer - yes, bad (uploaded image is Explorer)
Outlook 2013 - no
Word - no, including down to 6pt
Excel - yes, sometimes. I run a spreadsheet set at 10.5pt and tried altering the type size on individual lines. There is some splitting at 10.5pt (not too bad) and below (tried at 8 & 6). At 12/14/18pt no colour split occurs.
Filezilla - yes (as bad as it gets, a bit worse than my photo) I would try changing the typeface but there does not seem to be a way to do so.
Notepad++ - yes but not too bad.
Alleycode - yes but not too bad in both TXT and HTML modes.
Advanced System Care - no.
Iorbit Uninstaller - yes but not too bad.
Driver Booster - yes but only just shows up.
Allway Sync - no.
Wildbit Search - yes but not too bad.
That should be enough!

Regards
David
 

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Oh wow that does look like a weird issue! To be honest it looks like an issue with your TV rather than the GPU or computer itself - just looking at some comments in a review and this stood out:
"While this television does technically support 4K, the color depth is 8 bit and the chroma sampling is 4 : 2 : 0 when displaying that resolution. This may explain why LG calls its HDMI port "HDMI 4K @ 60hz" instead of HDMI 2.0."
This could go a long way in explaining some of the issues you're having. Have you checked to make sure that all the post processing options are turned off on the TV itself?
Could you try 1440p resolution and see if that changes anything? (2560 x 1440)?
 
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