4k monitor flickering at full resolution

I recently bought a 4k TV (LG 49UB820V) as a monitor for my PC. But I have many problems with my current configuration:

The image is by far not sharp, which it should be on a 4k monitor
Whenever the mouse moves the area around the mouse flickers a lot
Windows and the NVidia control panel show the native resolution as 1080p, which should be 2160p

All my hardware should support 4k@60Hz, but it just does not work. I tried changing the frequency to 50, 30 and 24Hz, but that did not help either.

I am using: NVidia GTX 960 and HDMI 2.0, Driver version 347.88, Windows 8.1 Pro 64-bit

Does anybody have an idea what the problem could be?

LittleEwok

Posted 2015-04-26T11:54:29.470

Reputation: 101

HDMI cable… is it v1.4 or higher? Use the one that came with the TV if you have more than 1. – Tetsujin – 2015-04-26T11:58:11.813

I bought one which explicitly had HDMI 2.0 compatibility – LittleEwok – 2015-04-26T11:59:25.143

Old question that just got bumped. The problem is your computer is seeing the TV as 1080p. The various symptoms are from mapping the 4K application output to 1080p, and the TV is then mapping the 1080p onto 4K. Why that's happening is the problem you need to solve. The cause isn't knowable from the symptoms; there are many potential problems in the chain. You need to systematically diagnose from one end of the chain to the other until you find it, and don't assume that components are working without verifying; e.g., just because the cable is rated for HDMI 2.0, don't assume it isn't defective. – fixer1234 – 2019-08-05T20:59:03.720

Answers

Check the cable is compatible with 4k:

http://www.hdmi.org/manufacturer/hdmi_2_0/hdmi_2_0_faq.aspx#119

Does HDMI 2.0 require new cables? No, HDMI 2.0 features will work with existing HDMI cables. Higher bandwidth features, such as 4K@50/60 (2160p) video formats, will require existing High Speed HDMI cables (Category 2 cables).

yobbo

Posted 2015-04-26T11:54:29.470

Reputation: 11

It is a High Speed HDMI cable. I've already tried two different cables. neither worked. – LittleEwok – 2015-04-26T12:24:29.563

-1

You do know that a TV is not a monitor right? Just because it supports output from HDMI, and your PC does output to HDMI does not mean a TV will give you the image a monitor would.

This is a common misconception. A TV is made to show video content, not pixel perfect content. Some TV's will do it better than others, but a monitor will always be a lot better at showing PC content. Thats why its called a monitor and not a TV.

So the flickering of the TV comes due to it having some trouble getting the pixel perfect to display correctly. It possibly downscales the HDMI output and applies filters to it. TV's do all kinds of tricks to make normal tv broadcasts look better, and thats where PC content gets distorted etc. See if you can disable all kinds of filters, it may improve your display. (by filters, think about smart refresh rates (100hz etc)

LPChip

Posted 2015-04-26T11:54:29.470

Reputation: 42 190

Well I know that a TV isn't the same as a monitor, but I have read many times that it can work just like that. I bought a TV because I needed the screen to have as many pixels as possible while still being readable as opposed to as 4k 25" monitor which is almost useless in my eyes. – LittleEwok – 2015-04-26T12:11:34.107

And I expect any 4k display to be pixel perfect since it is not analog. I don't think that is too much to ask for. The most annoying thing is the flickering when I move the mouse and I don't think this is really related to it being a TV but more to driver or misconfiguration. – LittleEwok – 2015-04-26T12:14:09.510

No, its definitely the fact that a TV pulls all kinds of tricks to make it appear smooth. This is due to the change from analog tv to digital tv. Digital tv uses a sync clock and pixel changes are instant, as opposed to analog where things blend smoothly. Because of that, screens that play on say... 60hz, will show flickering as pixels change. A mouse cursor or other images show big change in pixel quality. And as such filters try to compensate so it looks better. But with PC content, that either doesn't work, or screws up. I haven't seen a monitor where this doesn't happen, and I've seen many – LPChip – 2015-04-26T12:21:18.857

1I got rid of most of the flickering by playing with the TV settings. But it still bugs me that windows says its native resolution is only 1080p which is clearly not the case. I think this is at least part of the problem. – LittleEwok – 2015-04-26T12:33:26.280

Its possible (and likely) that your GPU cannot display a higher than 1080p resolution when using HDMI. I have to use dual DVI, or displayport to output to 2560x1440 myself. Can't use HDMI. – LPChip – 2015-04-26T12:38:31.307

The spec says it support 4k@60Hz with HDMI 2.0... – LittleEwok – 2015-04-26T12:45:27.687

To whoever voted this down, please explain why... – LPChip – 2016-03-25T10:33:48.217