Apple's remaining surprise....4K at 60Hz.

[thekev]

DP 1.2 will not ever support single stream transport of 4K @ 60hz.

It actually has the bandwidth, and the display output of thunderbolt 2 was seemingly based off that.

But hold on ... I guess I just wonder why, if DP 1.2 has enough bandwidth to send that many pixels pretending to be two displays, why that would somehow not be enough bandwidth to send exactly the same number of pixels correctly arranged as one display?

Just a poorly considered spec?

It's a problem with how they're manufactured. Where is the evidence that the specification does not provide for this? It sounds like speculation to me.

See also

http://www.vesa.org/displayport-developer/faq/

Q. What are some examples of where high performance is important?

A. DisplayPort’s high performance is important for enabling new digital display experiences. For example, DisplayPort can easily support high end monitors featuring Resolution up to 4K x 2K at 60 FPS and 24 bpp, Refresh rate up to 240 FPS for 1080p at 24 bpp, Color Depth up to 48 bpp, even at 2560 x 1600 at 60 FPS and Color Accuracy (provides in-band color profile data). In addition, DisplayPort enables long cable support, up to 15 meters, enabling a much anticipated easy plug and play digital experience with projectors. With DisplayPort, high performance is standard.

 

[anticipate]

I'm sure you saw this but did you enable 60Hz on the monitor?

These displays default to 30 Hz (instead of 60 Hz) and need to be manually configured to support 60 Hz using the display's built-in controls by enabling MST (multi-stream) mode.

For the Sharp PN-K321, you can modify this under Settings > DisplayPort STREAM

For the ASUS PQ321Q, you can modify this under OSD menu > Setup > DisplayPort Stream

 

[jbg232]

Everything I'm saying is speculation because the truth is that no one knows what the hardware will be able to do in a few years time. On re-reading the wonderful anandtech review he states:

...it is possible to drive a 4K display at 60Hz using a single DisplayPort 1.2 stream, the limitation today appears to be entirely on the monitor side. The first generation of 4K displays appear to be a bit of a hack. I’m not sure if the Mac Pro’s GPU hardware can drive upcoming 4K single stream panels or not as AMD specifically lists that as a feature of the new Radeon R9 series.

Thus, I now think that DP 1.2 can do it, but the mac pro gpu may not be able to do it. And the monitors definitely cannot do it at this time. Whether the mac pro GPU will be able to do it is not known at this point. Truth is, if anand doesn't know, no one does...

 

[Rich.Cohen]

MST/SST Why worry?

Why should I worry which is used if it works? Is this an issue of compatibility with future monitors or something more fundamental? Will I see an improvement if my monitor uses SST vs. a monitor with MST?

 

[Michaelgtrusa]

Only issue is that in 4k mode the text is way to small.

 

[goMac]

Totally a guess here, but isn't MST referring to hijacking the daisy chaining of display port to drive four displays instead of one? DisplayPort 1.2 supports 4 1080p streams, which happens to be the same number of pixels as a 4k display. You just have to combine the 4 streams into one, hence MST.

I wouldn't think there would be any quality difference, the only difference would be that you wouldn't be able to daisy chain displays. I don't know if that impacts Thunderbolt daisy chaining, but it would impact DP daisy chains.

 

[kamcma]

Totally a guess here, but isn't MST referring to hijacking the daisy chaining of display port to drive four displays instead of one? DisplayPort 1.2 supports 4 1080p streams, which happens to be the same number of pixels as a 4k display. You just have to combine the 4 streams into one, hence MST.

That's exactly what MST refers to, except it's combining two streams, not four, into one. The 4K displays generally divide the screen real estate in half vertically. Assuming the graphics card and connector (DP 1.2) have the bandwidth to handle it, it must be handled correctly by both the graphics driver and the display. All 4K displays so far are this way. OS X's graphics drivers only support it so far for the Sharp and ASUS 4K displays. Many people are hoping that OS X soon adds support for the Dell 4K displays. (Again, all of this paragraph is only relevant if you want 60 Hz, which most people do. If you only want 30 Hz, those Dell displays are already supported.)

What I was asking is if when later-generation 4K displays, manufactured without the MST hack to support 60 Hz, come out, will existing Macs with DP 1.2 support those displays. They should theoretically be able to, because, with one display at least, there wouldn't be an increase in the number of pixels being pushed.

 

[Rich.Cohen]

Only issue is that in 4k mode the text is way to small.

Not if you have a 50" screen. That's why I'm considering a Seiki 50" HDTV.

 

[DrManhattan]

24hz is what you're going to want anyway if you're going to buy a 4K TV or Projector. Of course most of the consumer 4K tv's now don't support 24hz yet anyway so you're going to have to wait for that. And wait for some media.

 

[Browsing]

What I was asking is if when later-generation 4K displays, manufactured without the MST hack to support 60 Hz, come out, will existing Macs with DP 1.2 support those displays.

That is exactly the same question about which I am wondering. I would like to keep the nMP for a few years, and I am sure in that time an affordable single stream UHD 60Hz monitor will show up...

I asked the same question in the Apple support forum, and I was answered in a simple but very effective way with the link to the official document about the nMP's support of 4K monitors. It was pointed out to me that if 4K 60Hz SST support is not present in the official docs, I should consider it non existent.

(Crap)

 

[handheldgames]

1) HDMI support beyond 1.0 specifications is also non-existent. While Macs are more than capable of supporting 4k @ 30Hz over HDMI, Apple limits the bandwidth to 165Hz rather than the expanded specification of 330Hz that was updated in 2006.

2) Apple's drivers also lack the ability for users to set color space on HDMI connected displays, in most cases reverting a full spectrum RBG/YUV 4:4:4 capable device to a limited 4:2:2 signal. While there is a "hack" available to address this, it doesn't work in all situations and is well.. a hack...

3) Running a 30Hz 4k display over a DVI connection or a non-active MDP connection is limited to delivering a 1/2 size MST image for a non MST device. Although the UI reports sending a 3840x2160 image, it sends a 1920x2160 image..



IMO... the state of Apple's video drivers are rather embarrassing... Perhaps testing on products that don't have the Apple Logo on them would be a good thing!

That is exactly the same question about which I am wondering. I would like to keep the nMP for a few years, and I am sure in that time an affordable single stream UHD 60Hz monitor will show up...

I asked the same question in the Apple support forum, and I was answered in a simple but very effective way with the link to the official document about the nMP's support of 4K monitors. It was pointed out to me that if 4K 60Hz SST support is not present in the official docs, I should consider it non existent.

(Crap)

 

[chfilm]

So can we sum things up for those of us who kind of lost sight in all this techy language jungle?

If the nMP is capable of displaying a 4k Image at 60hz via displayport (on the sharp for example) (and this is done through MST?)

it should be able to do so on future 4k displays as well, even when they use just a single panel. It's just a driver thing? Or is there a real technical barrier in the way?

I really can not imagine we won't be able to utilize any other 4k displays than the one they're shipping it with in the future, not how they market the thing.

Or am I drawing wrong conclusions?

 

[slughead]

1) HDMI support beyond 1.0 specifications is also non-existent. While Macs are more than capable of supporting 4k @ 30Hz over HDMI, Apple limits the bandwidth to 165Hz rather than the expanded specification of 330Hz that was updated in 2006.

This may be OT, but maybe you can answer this: what's the max resolution possible at 120Hz with current HDMI/DP technology?

 

[MacVidCards]

1) HDMI support beyond 1.0 specifications is also non-existent. While Macs are more than capable of supporting 4k @ 30Hz over HDMI, Apple limits the bandwidth to 165Hz rather than the expanded specification of 330Hz that was updated in 2006.

A cranky gentleman in Switzerland got me to drag a GTX680 to the 4K.

(He was complaining that he couldn't get 4K res via HDMI AT ALL)

So, here is breakdown:

1. In 10.8.5 GTX680 suffered from 165Mhz Pixel Clock restriction, so limited resolutions on HDMI. DP can do 4K at 30Hz.

2. In 10.9 HDMI support on 680 went up to 4K 30Hz

3. In all current Betas of 10.9.2 and latest Nvidia leaked drivers, there is still only 4K 30 Hz support. (Can't speak for how MBP with GTX750M does)

4. In 10.9.2 Betas, the AMD 7950 and 7970 ARE able to do 4K 60Hz. Pretty amazing and I'm hopeful that final 10.9.2 will have this as well. I don't know where the 2nd stream is borrowed from so I don't know if it can do 2 @ 4K 60Hz or if running one DP @ 60Hz turns 2nd one off. If someone wants to loan (or give) me a 2nd Asus or Sharp, I'll happily post the answer.

I would guess that 7870 can as well, I'll have to drag out the "in progress" AMD box, also has a 7770. Will be sad if a lowly 7770 can do 60Hz and a mighty Titan is stuck at 30Hz.

I have found a place I can tell right away the difference. I have been playing a (scary) game called "Dead Space" in Windows. I use 2 @ Titans SLI'd to keep framerate up. If I forget and leave in 30Hz mode, the guy flickers and jumps as you move or turn. Very noticeable and makes game unplayable. Unfortunately you have to exit game, push an infuriating sequence of 10 button pushes, then restart game. But at least the guy moves smoothly then.

In OSX you can tell how the cursor moves across screen. 30Hz has it jumping and disappearing. At 60Hz it is much smoother.

 

[kamcma]

A cranky gentleman in Switzerland got me to drag a GTX680 to the 4K.

Could you specify if you mean 680 with PC firmware or flashed for Mac, or the formal Mac Edition of this card?

But thank you, this information is very helpful

 

[MacVidCards]

Could you specify if you mean 680 with PC firmware or flashed for Mac, or the formal Mac Edition of this card?

But thank you, this information is very helpful

This one is running Mac EFI but I doubt that it matters.

 

[kamcma]

This one is running Mac EFI but I doubt that it matters.

I ask because, all else equal I'd rather get the official Mac Edition from EVGA, but their listed specs and their reps in their own forums say that the Mac Edition is DisplayPort 1.1 and somehow both DP and HDMI are limited to 2560x1600 in OS X but not Windows in Bootcamp? Very confusing, and anyway rings false, given a ) what the card is capable of under Bootcamp, b ) that the PC versions of this card are capable of 4K and c ) that it's based on the same chipset at the K5000 which is very much capable of 4K under OS X.

Anyway, I'm kinda hoping that OS X will in the near future be updated to support Dell's MST scheme, then I'd get the GTX 680 Mac Edition and see if my hunch that it really can do 4K under OS X is right.

If anyone has an thoughts on the matter, I'm all ears.

 

[MacVidCards]

I'm sorry if I'm not being clear.

I have an Asus 4K display. (PQ-321...identical to one Apple sells from Sharp, just a re-brand)

I have an EVGA GTX680 2GB.

In 10.8.5, you get 4K @ 30 Hz from DP but not from HDMI.

In 10.9, both DP and HDMI give 4K @ 30 Hz.

There is no MST driver yet but there are signs that it is being written and will get here after 10.9.2.

So, you can believe me staring at a screen or some guys posting specs.

Many, MANY cards can do 4K 30Hz from DP in 10.9.

I can't speak for the Seiki and Dell displays as evidently people have more trouble with them.

It makes sense that Asus & Sharp will be best choices right now since that is the display Apple is pushing.

 

[Anim]

What is the intended purpose of a small 4K display at 30Hz?

30Hz is right for realtime playback of NTSC/PAL video so I assume that is the real intended purpose?

30Hz is not a display you would want to use for development due to a choppy mouse (urgh). but more than this, with such a high resolution everything is going to be tiny isn't it?, I can understand it may be clear but it is still tiny which doesn't make for a nice development display.

Also, as the 4K content is so tiny on these displays, looking for artefacts and errors in video is going to be tough is it not? I can understand colour accuracy is the $$$ reason but that's it.

Why not just get a 50" 4K TV, wall mount it above your workstation and use that for playback. You could then have a couple of good quality 2K displays in front of you for developing on. Is that not a better rounded solution?

Sorry, I tend to waffle on. I am not a video editor so would expect some corrections to my musings here.

 

[handheldgames]

A cranky gentleman in Switzerland got me to drag a GTX680 to the 4K.

(He was complaining that he couldn't get 4K res via HDMI AT ALL)

So, here is breakdown:

1. In 10.8.5 GTX680 suffered from 165Mhz Pixel Clock restriction, so limited resolutions on HDMI. DP can do 4K at 30Hz.

2. In 10.9 HDMI support on 680 went up to 4K 30Hz

3. In all current Betas of 10.9.2 and latest Nvidia leaked drivers, there is still only 4K 30 Hz support. (Can't speak for how MBP with GTX750M does)

4. In 10.9.2 Betas, the AMD 7950 and 7970 ARE able to do 4K 60Hz. Pretty amazing and I'm hopeful that final 10.9.2 will have this as well. I don't know where the 2nd stream is borrowed from so I don't know if it can do 2 @ 4K 60Hz or if running one DP @ 60Hz turns 2nd one off. If someone wants to loan (or give) me a 2nd Asus or Sharp, I'll happily post the answer.

I would guess that 7870 can as well, I'll have to drag out the "in progress" AMD box, also has a 7770. Will be sad if a lowly 7770 can do 60Hz and a mighty Titan is stuck at 30Hz.

I have found a place I can tell right away the difference. I have been playing a (scary) game called "Dead Space" in Windows. I use 2 @ Titans SLI'd to keep framerate up. If I forget and leave in 30Hz mode, the guy flickers and jumps as you move or turn. Very noticeable and makes game unplayable. Unfortunately you have to exit game, push an infuriating sequence of 10 button pushes, then restart game. But at least the guy moves smoothly then.

In OSX you can tell how the cursor moves across screen. 30Hz has it jumping and disappearing. At 60Hz it is much smoother.

I just pulled a flashed EVGA 680GTX back out of the cabinet to swap out a Gigabyte flashed/resister-popped 7950 to give the latest beta a spin:

680 GTX: 30Hz @ 3840x2160 over HDMI or DVI works on a Seiki 39".

AMD 7950: 30Hz @ 3840x2160 over HDMI or DVI fails and is sent at 1920x2180. Based on your observations, it sounds like the blokes at AMD implemented MST/2160P over HDMI and missed the 30Hz boat. Getting 3840x2160 @30Hz requires an in-line/active single link DVI to mdp adapter.

FWIW... I use the Seiki 39"($400 street price) primarily for developing iPhone Apps. Whilst 30Hz is a drawback, it works great for writing / debugging code.

 

[Raddock]

What is the intended purpose of a small 4K display at 30Hz?

30Hz is right for realtime playback of NTSC/PAL video so I assume that is the real intended purpose?

30Hz is not a display you would want to use for development due to a choppy mouse (urgh). but more than this, with such a high resolution everything is going to be tiny isn't it?, I can understand it may be clear but it is still tiny which doesn't make for a nice development display.

Also, as the 4K content is so tiny on these displays, looking for artefacts and errors in video is going to be tough is it not? I can understand colour accuracy is the $$$ reason but that's it.

Why not just get a 50" 4K TV, wall mount it above your workstation and use that for playback. You could then have a couple of good quality 2K displays in front of you for developing on. Is that not a better rounded solution?

Sorry, I tend to waffle on. I am not a video editor so would expect some corrections to my musings here.

As a graphic designer, a small 4K display like Dell's 24" would be nice. You can run it in High-DPI/retina mode and have a retina 1080p display.

I would however prefer something slightly larger like a retina version of Apple's 27" monitor. Given that TB2 can't actually display a proper pixel doubled 27" monitor I would be ok with the alternative which is a pixel doubled 27" image (5120×2880) scaled down to 4k displayed on a 27" size monitor at 4k. (see here for a better explanation http://www.marco.org/2014/01/08/retina-imac-mac-pro-prediction)

 

[kamcma]

I'm sorry if I'm not being clear.

No, thank you for clarifying further and for being helpful. I do believe you.

The fault from where I'm sitting appears to be with EVGA putting out incorrect information about their own card, which is confusing as hell.

But now that you've reiterated, I feel safe in going ahead and getting this card.

----------

[/COLOR]As a graphic designer, a small 4K display like Dell's 24" would be nice. You can run it in High-DPI/retina mode and have a retina 1080p display.

Bingo. Retina 1080p at 24 inches is usable, for my purposes anyway. As long as you have to turn retina on with the command line and only get 2-for-1 scaling, then 24 inches of "1080p" I think will provide the most normal experience.

But looking forward, one would hope that eventually virtual resolutions will make their way to the nMP and old Mac Pros with 4K capable cards, just like the rMBPs have.

 

[Anim]

As a graphic designer, a small 4K display like Dell's 24" would be nice. You can run it in High-DPI/retina mode and have a retina 1080p display.

I would however prefer something slightly larger like a retina version of Apple's 27" monitor. Given that TB2 can't actually display a proper pixel doubled 27" monitor I would be ok with the alternative which is a pixel doubled 27" image (5120×2880) scaled down to 4k displayed on a 27" size monitor at 4k. (see here for a better explanation http://www.marco.org/2014/01/08/retina-imac-mac-pro-prediction)

Thanks for posting that. Retina is more complex than I first thought when it comes to displaying anything with the scaling of individual elements but I see that it works really well, especially if you want shots at 100% and still visible while maintaining the UI at readable sizes.

After reading the link you posted I also followed their other link to this post:
http://www.anandtech.com/show/6023/the-nextgen-macbook-pro-with-retina-display-review/6

So cheers. I learnt something new today

 

[MacVidCards]

AMD 7950: 30Hz @ 3840x2160 over HDMI or DVI fails and is sent at 1920x2180. Based on your observations, it sounds like the blokes at AMD implemented MST/2160P over HDMI and missed the 30Hz boat. Getting 3840x2160 @30Hz requires an in-line/active single link DVI to mdp adapter.

I think it's the monitor.

Just was trying to see what 3 @ 7970 could do for OpenCl (shocking !) and tried HDMI with the Asus.

Does 4K @ 30Hz in 10.9.1. but.......some blurring and color blending. Switching to DP made it much Sharper (pun intended)

In any case, HDMI did 4K 30Hz via HDMI, though not optimally.

Or did you mean that 10.9.2 kills this to do the 60Hz? I can pull 10.9.2 drive from 3,1 and test if you think so.

 

[mikeboss]

did anybody test if 4k @60Hz works when using the new NVidia WebDriver?
http://www.nvidia.com/download/driverResults.aspx/73628/