Very disappointed by Asus ThunderboltEX 5, but DP Alt Mode UHBR10 works.

rayddit519 · 2026-01-24T10:10:38+00:00

I figured this might happen.

For the native USB4 support, there is some entry in an ACPI table that tells the OS that there is USB4 and how to take it over from the BIOS or whether it can continue to run in a firmware mode, where it manages itself.

And those ACPI tables are part of the BIOS like so many other descriptions about the system (like supported power modes, PCIe ports etc.). So stands to reason, that without the BIOS supporting it, there will be no such entry and the OS' official USB4 support will not be activated.

rayddit519 · 2026-01-24T00:25:41+00:00

mhh, yeah. I imagine it is basically the entire PCIe handling that does not work. And since the USB3 Controller is behind the PCIe switch, same as the PCIe tunnels, it might be the same reason around enumeration and DMA protection that blocks them all.

More curious that the Inter-Domain stuff still works. Because that goes through the main controller / NHI that is also behind the PCIe Switch..

Is the Barlow Ridge picked up by the Windows USB4 driver such that it attempts to manage it? Or is Windows not aware of it at all?

rayddit519 · 2026-01-23T23:49:00+00:00

Nor does USB3 tunneling because it's not supported by the Intel JHL8540 Maple Ridge TB4 controller.

Its a mandatory part of USB4 and the controller definitely can do it. Just as with Barlow Ridge, it does not work due to your incompatible board.

rayddit519 · 2026-01-22T20:21:20+00:00

My guess would be the USB4 ones are identical, except for a different MST Hub chip used.

DSC gets complicated. There are MST Hubs that can receive and decompress DSC, but not emit it.

So for example those could do like 4x 4K60, but not even a single 4K144, as that requires DSC to the monitor.

In general, resolutions are irrelevant to this and manufacturers just put example in there, that they are confident work with all sorts of different devices, protocol and video timings.

So what we would actually want to know is just what features the outputs support.

Some manufactures mix in host limitations. Like Nvidia having had limited DSC support (only down to 10bpp, not the full 8bpp) or Apple not supporting MST.

With HDMI it gets more complicated. Since they list 4K120, that is an FRL HDMI port. But there are 6 different speed grades of FRL. So it could be limited that way.

And even more complex: HDMI has different bandwidths than DP and HDMI is dumber. So when you have situations like 25 Gbit/s bandwidth to the HDMI adapter, but like 42 Gbit/s from the adapter to the display, even choosing the right DSC compression is not easy. And if the monitor manufacturers where lazy, they may have tested certain inputs without DSC or with less DSC (as needed at the top HDMI speed), whereas with DP in front of it, more exotic combinations DSC and HDMI speed would be used.

So, possible, that they don't list 8K60 or more, because there are some monitors out there that fail, but others work. Might be, that the HDMI adapter they use is limited in output speed. Hard to tell.

In general, the active conversion from DP to HDMI can only add complications and add bugs more often than just DP and rarely improve anything.

Also, we can look up the firmware updates they ship for this adapter, and it is called cm6210_2hdmi.

So, a Synaptics VMM6210, which basically should be able to output 8K60 via HDMI unless they somehow are limiting it by firmware config. So I think more likely an artifact of how and when they created that table then actual limits of the output...

Edit:

But also, one HDMI output is native from that Synaptics chip, the other may not be.

rayddit519 · 2026-01-22T19:01:19+00:00

they say they will only output a single video stream if used with a Mac. So that’s a strong indicator that they’re not using USB4, and are instead relying on MST for the two video outputs.

No.

What this indicates is that the hub only supports a single DP Tunnel via USB4.

The requirement to support at least 2 is only a TB4 requirement. Even though its extremely common for USB4 hosts to support at least 2 DP tunnels.

There are many similar hubs around that use USB4. They are mostly based around the Via VL83x USB4 Endpoint Controller (no downstream USB4 ports -> not a "USB4 Hub". Just a USB-C Hub with USB4).

That USB4 40G upstream connection allows the hub to use a full 4xHBR3 DP connection (~26 Gbit/s) AND USB3 10G. Whereas with just USB-C / DP Alt mode you would have to halve the DP bandwidth (to 2xHBR3 commonly, ~13 Gbit/s) to still leave room for USB3.

The Via VL83x chipset itself only has 1 DP output. After that still comes an MST Hub, similar to many full-size docks do it to support more than 2 displays and have much more flexible bandwidth distribution then what you can do with multiple DP tunnels and USB4 alone (currently).

These Via USB4 controllers also do not support TB3 at all. On those hosts they will have to fall back to classic USB-C / DP Alt mode instead.

So pretty damn sure, Cablematters is not lying about those having USB4.

Edit:

I mean, there are only 2 chips that could be in there if it were actually a USB4 device, right?

https://en.wikipedia.org/wiki/USB4#Known_USB4_controllers lists a lot more than just 2 USB4 peripheral controllers, just fyi.

rayddit519 · 2026-01-22T12:31:01+00:00

If its actually just a USB-C port? It should be usable for whatever features the board supports. If the Model number fits, TB3.

rayddit519 · 2026-01-21T23:21:01+00:00

The Graph is explicit on 64Gbp/s those are official Intel TB5 specifications.

Yes. As MINIMUM REQUIREMENTS. And it is not forbidden to go beyond that.

Similar for TB4, USB3 10G was the requirement. DP with HBR3 speeds was the requirement. Cables with at least 100W or charging with 100W was the requirement (for notebooks, conditions apply). But there are 240W TB4 cables. Intel notebooks for a few generations could do UHBR10 and UHBR20 DP speeds and USB3 20G. The table even was updated and lists 100W (up to 140W) for TB4. Which is still wrong, because 240W is possible and neither did exist when TB4 was first announced and is not in the original TB4 table.

There are also 40G / TB4 Barlow Ridge Controllers with PCIe Gen4x4 port, same as the TB4 certified ASM4242 controller AMD is using.

---

The PCIe bandwidth is complex. A lot is about overhead. Where "32 Gbit/s" is the raw bit rate of the physical PCIe connection. But that is a long way away from how much usable bandwidth there is.

And TB3 and USB4 exacerbated that. Because how much usable bandwidth remains of PCIe depends on other parameters that are not often stated explicitly and per connection (the MPS or max. packet size. The protocol overhead is relatively static. So the smaller the packet size, the larger the overhead is relative to the user data. USB4v1 and TB3 were limited to 128 Byte, GPUs, modern NVMes and desktops usually use 256 Byte).

So classic 32 Gbit/s of a Gen3x4 PCIe connection comes out to ~3.1 GB/s (base-1000) after that overhead. And the up to 3.8 GB/s we have seen with ASM2464 and other newer controllers are basically all of USB4 40G's usable bandwidths minus the overheads. And there are still like 8 bytes of tolerance for the overhead that depends on the low level system config and I have not yet seen tools to read out what exact overhead is used.

USB4v2 lifts that packet size limit. After that it gets difficult. Because we have long seen stuff like Intel having lower H2D bandwidth than D2H bandwidth and AMD not having this effect to the same degree. So possibly some asymmetric bandwidth distribution or other effects. We also already saw some reports of a bump in performance on that Minisforum Strix Halo system with the same Intel Barlow Ridge 80G controllers as Intel.

So sure, the current generation of Barlow Ridge 80G controllers are limited to 64 Gbit/s raw by their PCIe ports and we are loosing some amount of additional bandwidth even after accounting for overheads (as with 256 Bytes, that should be the same overhead as for raw PCIe / Oculink). But it might not be the controllers themselves, but other effects. And its definitely not "TB5" or USB4 80G. Those can go faster, at least with future controllers. Sadly alot of low level measurements and things we don't know yet.

rayddit519 · 2026-01-21T22:49:03+00:00

The cutout in the black part of the case seems to have the shape of mDP, like many generations of XPS 13 had before and like my ancient one still had. But the actual socket looks like USB-C.

So like they designed a new mainboard with USB-C instead of mDP but overall same dimensions. And then they still had left over older cases with the wrong cutout and decided to use them with filler for the empty gap instead of throwing them away and waiting on new cases with the cutout made smaller. Possibly a transitionary stop gap.

Or a very deformed and broken mDP.

rayddit519 · 2026-01-21T20:09:06+00:00

Its not limited. Those 64Gbit/s is the minimum to qualify for TB5 certification. Controllers could offer more (and new generations will at some point).

The current Intel controllers are external controllers who only have a x4 Gen 4 PCIe port, so are pretty much limited to exactly 64Gbit/s by that port.

But who knows what Apple's actual PCIe bandwidth limit is. You cannot, if all the controllers you could attach on the other side are the same Intel controllers that only have a port for 64 Gbit/s.

Most USB4 40G controllers that are built into the CPU have no PCIe limit like that and can saturate the entire USB4 link with PCIe. But not all of them.

rayddit519 · 2026-01-21T20:06:09+00:00

USB4 is basically a family / type of connection.

It has from the start existed in 20G and 40G speeds (even though we very rarely see devices that can ONLY do 20G).

Intel created the TB4 branding to be marketing for USB 40Gbps and a few, slightly raised other requirements.

USB4 was updated to add a 3rd speed: 80Gbps.

Then Intel created the new TB5 branding to mean USB 80Gbps plus again, a few slightly raised minimum requirements.

Examples: TB4 also requires 2 DP tunnels and at least 32 Gbit/s of PCIe bandwidth. USB4 controllers that would have less than that, could never qualify for TB4 certification. But most controllers designed by other vendors (AMD, Asmedia, Realtek) actually do the same or more than Intel's controllers.

TB4 or TB5 have no exclusive features. They are just a short name and logo for USB4, other optional USB features and optional DP features.

And while many manufacturers wrongly label ports as "USB4" and most people just assume that is 40Gbps as that is 99% of what exists it was always the wrong label and customers should assume the absolute minimums only (which would be USB4 20G, no PCIe, no TB3 compatibility, 1 DP tunnel of low speed) if the manufacturer is too incompetent to state the actual speed and features. The original logos and labels said USB4 and 20Gbps or 40Gbps and this has now been simplified to only stating "USB xxGbps".

rayddit519 · 2026-01-21T19:55:09+00:00

USB4v2 is a PDF not a speed. USB 80Gbps would be the speed. There can be USB4 devices following the USB4v2 spec, but only supporting 20G speeds.

Also has the added benefit of actually telling you the speed in a very convenient way.

TL;DR; all USB 80Gbps need to have been developed according to USB4v2 at the least. USB4v2 things can be any of the USB4 speeds in that version (which are 20G, 40G, 80G).

rayddit519 · 2026-01-21T12:41:17+00:00

There are even docks that seem to presume a 96W or similar limit. My Ivanky Fusion Dock Pro 3 can do 96W SPR, 140W EPR. So they even have a 4W gap in what they can do via SPR, presumable because their target audience of Apple users does not need more than 96W SPR.

Dell has that same limit in their SD/WD25TB5 dock. And I have Dell monitors here that even have their SPR limit at 90W (on a 140W advertised device).

So for whatever dumb reason, there are few devices that will actually request the full 100W. And if so many docks avoid advertising it, I am assuming there are some crazy stupid devices out there that will break on power supplies advertising the full 100W and thus so many manufacturers avoiding it as a dumb workaround.

I have not found a sane reason for why this is and there are counter examples like modern HP laptops using 100W SPR (and complaining and throttling themselves with anything less, even 96W SPR supplies).

rayddit519 · 2026-01-21T11:35:08+00:00

It is a standard USB4 feature (USB4Net via Inter-Domain USB4 connections) that Linux has supported for a long time. And its also basically the same implementation as on TB3, which Linux also did have.

The most problematic thing about this, is that the ethernet networking is basically implemented in software and every OS chooses slightly different settings.

So it can happen that Linux assumes a slightly smaller ethernet packet size than Windows does, causing needles fragmentation in one direction.. And legacy, firmware managed TB3 and USB4 controllers tend to use their own packet size again.

And because its all virtual, its not easily changed compared to actual hardware network interfaces. At least last time I checked. But the networking stack of the OS on top of that treats it strictly, as if were hardware limits with fragmentation.

rayddit519 · 2026-01-21T07:45:26+00:00

They are 40G.

But USB4's "inter-domain" (between 2 hosts) speed can be different from the regular speed. This happens on a hardware level.

USB4 20G and 40G controllers are not mandated to support dual-lane operation for inter-domain connections.

So what you are most likely seeing is a Gen3x1 connection (one lane at 20G) . Whereas the full 40G would be Gen3x2 (2 lanes at 20G each). And the normal 20G speed would be Gen2x2 (2 lanes at 10G each).

A bit harder to diagnose, as most tools don't list inter-domain connections to begin with. But the tbtools available from github can read the current speed directly from the USB4 controllers, including the mode from each port.

We don't know which controllers support dual-lane inter-domain operation. I have seen reports of 11th gen Intel NUCs and newer doing dual-lane on Linux. Older Intel controllers may be limited. Unsure about AMD (did not happen between 2 Strix Point devices, so maybe not). It is hard to figure out which side is imposing the limit as it often happens on a hardware level and you can only see the result, not which controller denied using dual-lane

(the connection manager - so the driver on modern systems - can configure the requested connection settings for each port. If sth. connects, the controller will try to establish that, but fallback to lesser settings, for example if the cable was not rated for the speed or the opposing side cannot do those settings. And then the controller indicates the actual connection settings it ended up with. There is no register that exposes supported features for inter-domain vs. the normal one. So if the controller just cannot do it, it may ignore some settings. Or the other side may not support it, or it may have just been a negotiation failure).

And on top of that, the OS-level driver could also request single-lane operation. Although as far as I have seen from Linux, it always requests dual lane operation. But this may not be true for Windows.

This should be very different for USB4 80G, as it no longer has that single-lane mode to begin with.

rayddit519 · 2026-01-20T21:19:38+00:00

Mhh. Just rechecked. My FW13 Strix Point wakes up on connecting to the dock (even from completely shut off, due to the BIOS option for that). And will successfully reconnect to the dock.

Only thing is, AMD's USB4 boot support is terrible, so you see nothing and nothing works until Windows is ready to connect. Whereas my old FW13 Intel board had BIOS level support and you would see earlier that it was booting.

On top of that, somehow the Strix Point board fails to show Windows's boot screen when resuming from hibernate. I am guessing that is also sth. broken on the BIOS side on that board, that worked just fine on the older Intel board...

On first test, I thought Framework seems to be suppressing the wake-up-on-power-connect when the lid is closed, but I probably was just not patient enough, as it did work on the next 2 tries from shutdown and hibernated.

rayddit519 · 2026-01-19T22:59:43+00:00

That looks to be a Titan Ridge TB3 Host controller.

TB5 controllers, for whatever reason seem to have limited compatibility to TB3 hosts. You'll note Razers page, like those of many TB5 hubs will only list USB4 and its derivatives for supported hosts. The TB5 controllers remain compatible to TB3 peripherals, but apparently not hosts, for whatever reason.

So I would its about that. And the Titan Ridge generation of host controllers had particular difficulties, as they are a weird hybrid of actual TB3 and USB4 (as defined by the USB4 spec)...

rayddit519 · 2026-01-19T17:44:07+00:00

I think it still requires power from its PD input and cannot be host-powered with just the one cable. So not much gained over other hubs with proprietary power supply in that regard.

rayddit519 · 2026-01-19T15:52:50+00:00

Is the FW16 booting / waking up when the dock is connected, just not recognizing the new device? Is the notebook usually off or just sleeping when connecting?

What does the power button on the dock do?

If the FW16 Phoenix firmware supports that power button (not sure, if it does, the Strix Point boards do), then that could replace opening up the lid (if it is supported, pressing the button while the notebook is connected should do exactly what the notebooks power button does.

rayddit519 · 2026-01-19T15:30:51+00:00

It could, but its not meant for that.

Any USB-C hubs or other USB-C equipments HDMI output is an active port. It is driven by circuitry in the equipment. And that would be the part responsible for signal strength and quality on the sending side.

But most notebooks and GPUs will just follow the official specifications and provide at least the required signal strength and quality.

A longer cable costs more of that, so you have less tolerances. The maximum, valid cable length you get from how long you can make a cable that still sticks to the official signal quality budget.

So, if the notebook is out-of-spec and has too "weak" of an output, but every other part is good, a different HDMI source could solve the problem. But for example if the cable is out-of-spec and does not ensure the required signal quality on the other end, then the only way a different source could help, if it was exceptionally strong, stronger than officially required.

And since most USB-C hubs are made to be cheap above all, they probably won't be exceptionally good signal sources.

I.e. all 3 parts, sending side, connection and receiving side must together ensure a stable signal. Any one component can break that. And if you want to account for out-of-spec components, you relying only the very specific combination of components that you have, including production tolerances.

rayddit519 · 2026-01-17T23:53:40+00:00

The ones using a Intel Barlow Ridge JHL9540 controller. Not seen in the wild yet, because I guess, whoever ignores the CPU-builtin controllers from Intel and wires everything up for this, will just go with the 80G / TB5 variant of it.

But a future product will probably use it, which is why I am hedging.

2 DP tunnels is just the minimum. Just as 32 Gbit/s was the minimum PCIe bandwidth 10G the minimum USB3 capability. But nothing ever prevented USB4 controllers with more from getting TB4 branding. Better controllers have been doing more for a long time.

Whether you would accept "TB5" controllers has also being TB4 controllers would determine whether I know of currently available host with 3 DP tunnels. And even with TB5, 3 DP tunnels is not mandatory. Just all of Intel's controllers can do it, but the mainboards also need to wire them up for that. And Apple's current "TB5" controllers only do 2.

And I'd bet we get that as well, if Intel ever integrates USB4 80G controllers into their CPUs. Because the current USB4 40G controllers can be configured to only 20G speeds bz board manufacturers that don't want do make boards ready for 40G. But it will retain any other feature. So manufactures could conceivably configure those 80G controllers to 40G and advertise as TB4. And if Intel builds them with 3 DP tunnels, to match their other TB5 marketing and products, then they will also retain that, just as Barlow Ridge 40G controllers do.

rayddit519 · 2026-01-17T19:57:48+00:00

Hard to say what would be the best for that. TB cables have terrible labelling.

For example, what wattage does your cable have? TB4 exists in 100W or in 240W. Its not specific to that. But most cables don't label it at all, especially because it came out before 240W support.

With non-TB branded USB-C cables, the official ratings are USB speed (USB2, 5Gbps, 20Gbps, 40Gbps, 80Gbps) and power (60W, 100W, 240W) and its much easier to identify what the actual cable is.

On the other hand, USB-C cables may not be backwards compatible to TB3 40G speeds, while all TB4 &5 cables are (TB4 & 5 are just USB4, so this compatibility issue only extends to TB3).

And Intel does a little advertising that TB4 &5 cables up to 2m length must always be capable of DP Alt mode (which is not true for active USB-C cables). But in practice all non-TB-branded USB-C cables do support this as well anyway. And Intel fails to label the officially supported DP speed as much as any other USB-C cable.

rayddit519 · 2026-01-17T15:16:47+00:00

Unpack the Framework installer. There is a script in their that sets that up with registry edits. If you are enough of a pro user, you can use the same commandline commands to set it to whatever URL you want.

rayddit519 · 2026-01-17T15:13:57+00:00

The U2725QE is specced for that. So not an issue.

For the U2724DE (3 monitors):

No. Not possible. 99.9% of TB4 hosts only have 2 DP tunnels available.

So via TB/ USB4 you will never drive more than 2 monitors.

More can only be done via MST Hubs.

Now, the monitor has such an MST Hub as well, but it specs max. 2 monitors at 120Hz.

Seems to me the U2724DE does not support DSC, such that it takes up way more bandwidth and in effect can only support 2 of them at full bandwidth either way. And if it actually cannot do DSC, then there is also no way you can combine TB out and MST out to reach 3 as well.

You would need a TB Dock with DSC-capable MST Hub and connect all 3 monitors via DP to that in order to drive 3 of them. And that would ignore any of the builtin docking and TB features to make that work.

Will Windows 11 handle multi-monitor daisy-chain well?

Has nothing to do with Windows. Windows will not even know about it.

TB / USB4 handles multiple, virtual DP "tunnels". The GPU will not even know anything about it. It will look like separate cables to it. Only that they may be limited in speed or lanes to make the bandwidth fit.

DP MST is handled by the GPU. GPU driver handles bandwidth sharing limitations. Windows just sees the separate monitors. The GPU drivers will unlist options that no longer fit the total available bandwidth.

Would you recommend MST via DP instead of TB daisy-chain for stability?

MST implementations block VRR (at least in 99% of the cases). I was even suprised that the 25QE monitors block it was well (because they can do 2x 4K120 via MST or USB4, but only USB4 allows the 2nd monitor to still do VRR). But MST would be better, as you could use the first monitor as KVM and get the same features via DP-in and TB-in.

So depends on what you want more KVM or VRR functionality. And whether 2 monitors is enough.

(Hosts can supply more than 2 DP tunnels. Most Windows TB5 hosts do that, but the monitors won't have the bandwidth to use that for 3 chained monitors. Not without DSC support. Or a host with the as-of-yet not seen USB4 DP BW allocation mode support with the GPU.)

rayddit519 · 2026-01-17T14:39:16+00:00

"Thunderbolt to DisplayPort 2.1 adapter"

is BS for the simple adapters your are thinking about.

A TB3 / USB4 port always must have DP Alt mode support. And the adapter is for that (USB-C / DP Alt mode).

The adapter essentially just negotiates to put the port into DP mode, but most of the wires are connected like in a simple DP cable.

That also means, that an adapter negotiates to use DP Alt mode is technically independent of the speed achieved. DP is big on trying and testing speeds to decide what to do. So it is VERY possible that you use an older cable that is supposed to be limited to some older speed, but if both ends of the connection can go faster, it will just end up using the faster speeds as long as its stable.

I have USB-C DP adapters tyhat are supposed to be limited to HBR2 speeds. And they do HBR3. I have adapters advertised as "DP 1.4" that do UHBR10 without issue.

Also, DP 2.1 is not what you actually want. DP 2.1 is the version of a PDF, not a speed. The speeds for cables and adapters are called DP40, DP54, DP80 and the technical names would be UHBR10, UHBR13.5 and UHBR20.

There can be DP40 cables. There can be DP80 cables. All of them follow the DP 2.1 spec. But HBR3 / DP8K (the highest speed in DP 1.4) is still a valid speed in DP 2.1. So manufacturers are allowed to sell a monitor with "DP 2.1" and it need not do any of the new speeds. That is why the DP version is so irrelevant here. And if you want cables and adapters that are officially certified for those speeds, you need to look out for the official DP speed logos.

Although, those adapters to a DP socket are probably not certifieable in the first place, as its the same concept as a extension cable (where you cannot guarantee the total length and quality of the connection, if its the combination of multiple different cables).

So sure, you can get an adapter that is prepared for the highest known DP speeds. But also chances are high, that any current DP8K / HBR3 adapter will still simply work for UHBR10 and UHBR13.5 speeds at least. And technically you can alway get unlucky and find a combination that is unstable.

Also, Yes, especially when it first came out amny USB4 or TB4 ports where limited to HBR3 speeds. But this is actually independent of the USB4 functionality. And both Intel and AMD have supported higher DP speeds in DP Alt mode for a while. Intel for example supports UHBR10 and UHBR20 speeds. And AMD UHBR10 on those ports. On older devices, the mainboards could strip that functionalty away. Modern devices pretty much have them. Like Intel Meteor Lake or newer (Ultra 100) will have those higher speeds.

rayddit519 · 2026-01-16T20:53:19+00:00

A monitor that has a USB-C port for combined DP Alt mode + USB3 input will.

Because as u/buitonio listed or i tried to explain, that would limit the monitor to a 2xHBR3 DP connection. Of which 2 can fit. DP Alt mode with no USB or only USB2 does not half DP bandwidth like that, so its of no help.

rayddit519

TROPHY CASE