4K displays and Hz, HDMI 2.0+

[aandril]

So there are 4K tv's that have high Hz, Such as 120 Hz. There are 2K monitors that can go over 144 Hz. Etc.

 

Every description of HDMI 2.0 cable I've read says it only supports 60 Hz for 4K, up to 144 Hz for 2K, and like whatever higher Hz for 1080p.

 

So if my 4K TV has 120 Hz, and use it as a display for my laptop, it will be reduced because of the HDMI connection.

 

Same goes with a 2K monitor, that is if it is more than 144hz.

 

What's the deal with this?

[WereCat]

Your 4k TV certainly doesn't have true 120Hz.

It's using doubling which is quite a bit different.

[aandril]

1 minute ago, WereCat said:

Your 4k TV certainly doesn't have true 120Hz.

It's using doubling which is quite a bit different.

Huh?

[WereCat]

Just now, aandril said:

Huh?

Its 120Hz in the way that either every other frame is blank(black) or exactly the same as the previous one.

This does not require extra bandwidth, thus HDMI 2.0 is enough because it's the same as just using 60Hz, but the effect is still more pleasing to the eye rather than just using 60Hz.

[aandril]

1 minute ago, WereCat said:

Its 120Hz in the way that either every other frame is blank(black) or exactly the same as the previous one.

This does not require extra bandwidth, thus HDMI 2.0 is enough because it's the same as just using 60Hz, but the effect is still more pleasing to the eye rather than just using 60Hz.

I still have no idea what you're saying.

 

And my post is about the HDMI limits, reducing the Hz of the display......

[WereCat]

3 minutes ago, aandril said:

I still have no idea what you're saying.

 

And my post is about the HDMI limits, reducing the Hz of the display......

I'm telling you that yes, HDMI 2.0 can use 4k only at 60Hz, "2k" at 144Hz because it cant carry any more bandwidth to support higher refresh rates.

 

And I'm talking about why your TV is not actually 120Hz but it's 60Hz with some trickery.

 

When you connect your laptop to the TV and the laptop has HDMI 2.0 then you should have no problem running 60Hz. You can probably also enable the "120Hz" but you need to set a custom resolution and enable the particular refresh type that will double the frames (idk how it's called... interpolation?, not sure).

[aandril]

Hm alright. But if it can carry 144 Hz to 2K, why not 72 Hz to 4K?

 

If 72 Hz isn't such a huge change from 60 Hz and is considered pointless, and doubling Hz "doubles" framerate (30 to 60, 60 to 120), doesn't that mean you should just use 120hz as 144 is pointless?

[WereCat]

1 minute ago, aandril said:

Hm alright. But if it can carry 144 Hz to 2K, why not 72 Hz to 4K?

 

If 72 Hz isn't such a huge change from 60 Hz and is considered pointless, and doubling Hz "doubles" framerate (30 to 60, 60 to 120), doesn't that mean you should just use 120hz as 144 is pointless?

Because what you call "2k" is not actually "2k" but 1440p which is not half of 4k... wait... 4k is actually also different, we are talking about UHD.

[aandril]

8 minutes ago, WereCat said:

Because what you call "2k" is not actually "2k" but 1440p which is not half of 4k... wait... 4k is actually also different, we are talking about UHD.

Oh yeah?

 3840 x 2160 = 8,294,400

2560×1440 = 3,686,400

[WereCat]

13 minutes ago, aandril said:

Oh yeah?

 3840 x 2160 = 8,294,400

2560×1440 = 3,686,400

Hmmm.

True, but you still have to account for a color bit depth, chroma sampling, etc... You won't be running more than 8-bit 1440p 144Hz while you can run 10bit UHD 60Hz.

[aandril]

Ridiculous. I run everything in grayscale.

[Glenwing]

2 hours ago, aandril said:

So there are 4K tv's that have high Hz, Such as 120 Hz. There are 2K monitors that can go over 144 Hz. Etc.

 

Every description of HDMI 2.0 cable I've read says it only supports 60 Hz for 4K, up to 144 Hz for 2K, and like whatever higher Hz for 1080p.

 

So if my 4K TV has 120 Hz, and use it as a display for my laptop, it will be reduced because of the HDMI connection.

 

Same goes with a 2K monitor, that is if it is more than 144hz.

 

What's the deal with this?

The "120 Hz" is not the refresh rate of the display, typically it means the backlight strobe frequency, which is a motion blur reduction method that has nothing to do with refresh rate, they are just purposely vague about it hoping that if they just say "120 Hz" with no context you will assume they are talking about refresh rate.

 

If it does refresh at 120 Hz, then it still only takes 60 Hz from the source, it just generates its own frames by calculating what an "inbetween" frame might look like, which adds massive latency and is not at all good for gaming.

 

As far as I know there are no 2560×1440 displays that support more than 144 Hz over HDMI. If they support higher refresh rates like 165 Hz, it only works over DisplayPort.

[Peskanova]

Have you look if your tv has displayport? its like HDMI but with 1 flat side

HDMI standards for +60hz are "new" , we have for a long time 144hz over 1440p with displayport