What does Thunderbolt 4 support with minimal video requirements.

[KHe7]

What does Thunderbolt 4 support with minimal video requirements?

"Video: Support for two 4K displays or one 8K display." in https://newsroom.intel.com/news/introducing-thunderbolt-4-universal-cable-connectivity-everyone/#gs.ffzy64

With Thunderbolt 4 logo, all device could output 8K60p or not?

[JosueO_Intel]

Hello KHe7,

Thank you for posting on the Intel®️ communities. 

In this case, system manufacturers will be the ones in charge of defining the capabilities of the thunderbolt port on their computers. 

This is because OEMs customized their systems in order for them to work without any issues, in case you are looking for specific specifications on thunderbolt capabilities in a specific system, please contact the manufacturer in order to be able to get that information. 

Please keep checking our newsroom for the latest news on technology and more. 

Regards, 

Josue O.  

Intel Customer Support Technician

[KHe7]

Hello Josue, 

Thank you for replying to my question.

I thought Intel and Thunderbolt™ Community certificate devices for "Thunderbolt 4".

Quote requirements from https://thunderbolttechnology.net/tech/certification

Thunderbolt™ 4 certification requirements include:

• Double the minimum video and data requirements of Thunderbolt 3.
  - Video: Support for two 4K displays or one 8K display.
  - Data: PCIe at 32 Gbps for storage speeds up to 3,000 MBps.
• Support for docks with up to four Thunderbolt 4 ports.
• PC charging on at least one computer port. (For thin-and-light laptops that require less than 100 watts to charge.)
• Wake your computer from sleep by touching the keyboard or mouse when connected to a Thunderbolt dock.
• Required Intel VT-d-based direct memory access (DMA) protection that helps prevent physical DMA attacks. (Read more in the Thunderbolt Security Brief.)

In these lines, "Thunderbolt 4" certificated devices support for two 4K displays or one 8K display.

But "or" in sentence allows devices not to support one 8K display? (This question means "Thunderbolt 4" certificated devices allowed to just support only for two 4K displays without supporting one 8K display.)

Sincerely,

KHe7.

[n_scott_pearson]

So let's be clear: Thunderbolt doesn't have this magic capability to improve the capabilities of the systems graphics engine. All it can do is provide a transport capability for the existing graphics capability.

If an older processor that cannot support (at a reasonable frequency, for example) two 4K displays via a single DisplayPort signal (as would be the case on older graphics engines that only have DisplayPort 1.2 output capabilities), then receiving this signal over Thunderbolt isn't going to help you. Similarly, for 8K displays via split 4K signals, this can only be supported if the graphics engine (also) has support for this capability and the Thunderbolt IC has support for the input of two output signals.

Bottom line, you need to be looking at the capabilities of a single output stream from the graphics engine of your solution (processor or discrete) and not at the Thunderbolt transport capability.

Hope this helps,

...S

[KHe7]

Then I thought "Thunderbolt 4" just does not certificate laptops with old poor CPU and GPU(They might get lower certification like USB4 or Thunderbolt 3).

I just want to confirm "Certification Requirements" of "Thunderbolt 4".

10bit 4:4:4 8K30p is under 40Gbps and 10bit 4:4:4 8K60p with DSC is also under 40Gbps.

In my poor English, I could not judge "Video: Support for two 4K displays or one 8K display" require every device has "Thunderbolt 4" certificated port need  to support one 8K display, or not.

[n_scott_pearson]

You are just not getting what I am saying: Thunderbolt 4 is simply a TRANSPORT. It does not have anything to do with the graphics capabilities of a system other than it can provide a certain bandwidth for the transfer of graphics data. That it can pass the data necessary to handle two 4K displays or one 8K display is simply a real-world example of part of its capabilities - and, as I said, this is only possible if a (minimum) DisplayPort 1.4 signal is being supplied to the Thunderbolt 4 IC by the systems graphics engine.

...S

[KHe7]

Your replies did not understand main point of my question.

"CERTIFICATION REQUIREMENTS" ARE NECESSARY FOR ALL DEVICES CERTIFICATED WITH "Thunderbolt 4" as they literally mean.

I asked one of the companies they certifies host device with "Thunderbolt 4".

They answered testing devices with only two 4K60p display to certify as "Thunderbolt 4".

From this, I conclude "Thunderbolt 4" certification does not requires host devices support 8K.

"or" in requirements might allow not to support 8K.

I thought "Thunderbolt 4" is the most advanced port and should support 8K for 8K displays come major in few years, but unfortunately they do not.

[n_scott_pearson]

This is my final reply; this conversation is going nowhere. You are vastly off on a tangent.

First of all, they are simply talking about using two 4K monitors to verify that the Thunderbolt 4 implementation can meet the data throughput capability that it is supposed to. Secondly, your conclusion is drivel; this can also be accomplished using one 8K monitor - the data throughput requirements would be the same as for two 4K monitors. Of course, to do either, you have to have a graphics engine connected that can support the two 4K or one 8K monitors. Like that company, I would test with two 4K monitors simply because, right now, the two are cheaper than that 8K monitor.

...S

[KHe7]

Thanks for all your replies.
I focused on not cables but host devices, then we are so far away from each other.

I want to replace my 4K monitor with 8K one, and I prepare new laptop for this purpose.
But it is a advances usage right now, so many devices do not describe they support 8K or not.

So I tried to figure out they support 8K or not with "Thunderbolt 4" certificatation requirements. If "Thuderbolt 4" require host devices to support 8K60p, then I trust one with "Thunderbolt 4".
As I see, every laptop with "Thunderbolt 4" certified port equips with Intel 11 gen or 12 gen CPUs or GeForce RTX 30n0.

But "Thunderbolt 4" requires 8K60p or not is last problem.
No test with 8K for certification results they might not to support 8K, not trustable.

[n_scott_pearson]

No, no, no. You are making bad assumptions. The fact that a system might happen to support Thunderbolt 4 does not mean that this system can support an 8K monitor. Thunderbolt 4 is a transport; nothing else. In order to determine if the system can support an 8K monitor, you need to look exclusively at the capabilities of the graphics engine (whether discrete or integrated). Yes, it is true that you need to be looking at having an 11th or (better) 12th gen Intel processor and/or RTX 30xx graphics - but look specification at those features; don't make any assumptions based upon seeing Thunderbolt 4.

...S

[KHe7]

As I read your replies, you think that "Thunderbolt 4" logo beside port on devices means nothing for us.

I thought "Thunderbolt 4" logo on host devices ensure us that each host device supports their certification requirements.
No host device is certificated as "Thunderbolt 4" without supporting all of certification requirements, from literal meaning of certification requirements.
So, we trust host device with "Thunderbolt 4" for 40Gbps throughtput, two 4K displays, 15W power supply, USB4 compliant and etc from p.14 of https://thunderbolttechnology.net/sites/default/files/intel-thunderbolt4-announcement-press-deck.pdf

In addition, I want to confirm video support for 8K is included to "Thunderbolt 4" requirements or not.

[n_scott_pearson]

OMG, you are freaking killing me! Listen to what I am saying: Thunderbolt is simply a TRANSPORT.

With the exception of the USB4 and USB-C (and derivative) capabilities that it is required to support, Thunderbolt 4 simply provides a transport for other technologies (DisplayPort, PCIe, VT-d, etc. and etc.) to utilize. The fact that it supports the use of its transport capabilities for these other technologies this does not mean that these other technologies are present or supported by a particular Thunderbolt 4 port. Using video as an example, there is absolutely no guarantee that a Thunderbolt 4 port will provide support for video output of any kind; it does not have to and the specification does not say that it has to.

Bottom line, in your statement above, remove "two 4K displays" from the list of things to 'trust' are supported; it simply is not guaranteed to be the case. With the exception of the fact that 40Gb/s just happens to be enough bandwidth to support an 8K video display, there is no guarantee that a particular Thunderbolt 4 port will support an 8K video output capability (it might, but there is no guarantee that this is the case). Further, even if an 8K video output capability is provided, it is possible that, if the Thunderbolt 4 port is also being used for other purposes (PCIe, VT-d, etc. and etc.), there might not be enough bandwidth available to support an 8K display (at least not at the expected frequency or bit rate).

If you are interested in purchasing a system that supports an 8K display, you want to look for the following:

1. The presence of a graphics engine that supports an 8K display.
2. The presence of a port that supports an 8K display. This port should be one that is dedicated to the support of this display. This video port could be HDMI, DisplayPort or a Thunderbolt 4 port that supports DisplayPort.
3. Note that, when I say dedicated, I mean that it is preferable that the water not be muddied by having, say, a hub device that might be sharing this Thunderbolt 4 transport capability (through supporting multiple video ports, downstream Thunderbolt 4 ports, etc.).

...S

[KHe7]

Thank you for notify me about those lines which I missed.

And then everything that Intel and Thuderbolt Community said related to display support about "Thunderbolt 4" has cancelled.
The descripton like "Thunderbolt 4 support 2*4K displays" became completely lie. (They advertised and still public websites about their misleading propaganda without revise).
"Thunderbolt 4" certification promise us only 40Gbps bandwidth for transporting graphics.

----- What I did suppose about "Thunderbolt 4" ----- begin
What system supply "TO" the port | Certification of the "PORT"
2*4K and 1*8K | Thunderbolt 4
2*4K and 0*8K | Thunderbolt 4?
1*4K and 1*8K | Thunderbolt 4?
1*4K and 0*8K | Thunderbolt 3
4*2K | USB4
1*2K | USB4
----- What I did suppose about "Thunderbolt 4" ----- end

In the real world, there is the laptop has "Thunderbolt 4" port and HDMI 2.1 port with Core i7-11800H and GeForce RTX 3060.
Core i7-11800H supports 7680x4320@60Hz via DP 1.4.
GeForce RTX 3060 supports 4K120pHDR and 8K60pHDR via HDMI 2.1(but via DP is just discribed as 1.4a).
In this context, the laptiop may be able to supply 8K via HDMI or connect directly from Thunderbolt 4. (only maybe)

I have got conclusion that certification of "Thunderbolt 4" is nomeaning about display output.

[n_scott_pearson · Accepted solution]

Your final statement is correct (as is your bandwidth statement). For the rest of it, you have again read too much into it. No, there isn't any lie (why to people make idiotic statements like this?); it is simply you misinterpreting what you are reading. They are simply pointing out that the transport capability of Thunderbolt 4 is sufficient to support these (example) display configurations. This does not mean (and never did) that a particular Thunderbolt 4 port will offer these display capabilities.

As for your example,

• DP 1.4 and DP 1.4a are basically the same. In DP 1.4a, the DSC (compression) support goes from 1.2 to 1.2a.
• HDMI 2.1 offers roughly the same capabilities as DP 1.4. HDMI 2.1 supports DSC 1.2. 
• For information on DSC, start with the summary here: https://en.wikipedia.org/wiki/DisplayPort#Display_Stream_Compression.
• For information on DisplayPort bandwidth requirements, look at the charts here: https://en.wikipedia.org/wiki/DisplayPort#Refresh_frequency_limits_for_standard_video.
• For information on HDMI bandwidth requirements, look at the charts here: https://en.wikipedia.org/wiki/HDMI#Refresh_frequency_limits_for_standard_video. 
• Remember that the laptop plays a role in what is actually supported. As I said earlier, the way to ascertain whether 8K is supported (and how) is to (a) look it up in the laptop's specs (or contact laptop vendor - and ask for guarantee!) or (b) simply get a laptop and try it (if it doesn't work, make them take it back).
• My personal opinion? For 8K or for HDR, stick with the RTX 3060 solution until Intel gets their act together (I am still not enamored with the quality of their drivers).

...S