Why can't monitors receive 120hz over HDMI?

[Whitestar127]

Something I've just been wondering about after I had a look at the HDMI specs.

It seems since HDMI 1.4b it's possible to send 120hz over the HDMI cable, is that correct?

So why can't monitors receive it then? Are they on 1.4a or lower? I realize that Displayport has become the standard, but still...

And what is my GPU (GTX 670) sending? I looked at the specs on Geforce.com, but it just says HDMI, not which version.

Would be nice if someone could enlighten me.

EDIT: Or was 120hz actually supported from 1.4 upward?

 

[XavierMace]

Some monitors won't do 120hz, regardless of connection type.

 

[Whitestar127]

Sorry for the thread resurrection.
Nothing beats trying things yourself, so that's what I did. I bought a HDMI spec 2.0 cable and attached it from my 980 Ti to my Benq XL2411T.

Result: only 60hz available.

It seems most monitors just can't receive more than 60hz in the HDMI port.
Just posting this here in case others are wondering about the same thing.

 

[XavierMace]

120hz wasn't added until 1.4b. So unless your monitor has 1.4b or higher, it's not going to work. It's pretty straight forward.

 

[Nashemon]

I bought (and returned) a 4k monitor last year. It would only do 30hz over HDMI. Needed the display cable for 60hz. So, yeah, it depends on the monitor.

 

[Whitestar127]

120hz wasn't added until 1.4b. So unless your monitor has 1.4b or higher, it's not going to work. It's pretty straight forward.

Hmmm, are you sure it's that straight forward?

According to this guy: https://www.youtube.com/watch?v=FIQvQeGCkeU (03:40) it's a common misconseption that HDMI 1.4 (b) outputs 120Hz. Well, it does, but only in 3D. Disclaimer: I'm not saying he's right and I'm not saying he isn't.

The Wiki isn't totally clear on this: https://en.wikipedia.org/wiki/HDMI#Version_1.4. It says "One of the new features is that it [1.4b] adds the ability to carry 3D 1080p video at 120 Hz – allowing frame packing 3D format at 1080p60 per Eye (120 Hz total).

Would be nice to get a monitor manufacturer's comment on this. But anyway, it seems the monitor must support at least HDMI 2.0 for it to support 120Hz in 2D. It also seems it's very uncommon for monitors in general to do that, even gaming monitors. Probably because we already have DVI DL and now lately Displayport to cater for that.

 

[Squeetard]

It's not the hz that it can't push, it is the pixels. Not enough bandwidth on the spec.
120hz 3D is the same as 60hz 2d.

 

[XavierMace]

The HDMI spec defines what you CAN do with HDMI. That doesn't mean your monitor was built to do that. My point was that without 1.4 it CAN'T do 120hz over HDMI.