Gigabyte introduces Thunderbolt 5 PCIe 4 card with up to 120 Gbps of bandwidth, support for 100W power delivery

Li Ken-un said:

Intel just can’t stop making crappy Thunderbolt controllers… SMH

2 * 80~120 gbps-capable ports, but the bottleneck for PCIe traffic is 64 gbps (PCIe 4 * 4). I would’ve very much liked ASMedia’s approach of not assuming everyone funnels video traffic through the same cable being used for data.

This card should be PCIe Gen 5 * 4 at the very least.

Why would it be PCIe 5.0 when Thunderbolt 5 spec uses PCIe 4.0 for data?

TB5 data is 64Gbps, DP 2.1 is 80Gbps and the Asymmetric is only for video.

ezst036 said:

Nice card.

Problem is far too many full size ATX boards only have two slots on them. I think I've even seen some with 1 at all. Gone are the days when you commonly saw 5, 6, or 7 slots on a board. (which is what you should see.) or 3, 4 slots on an mATX board.

These motherboard makers have gone down a bad path by wasting all of that board space with flat M.2 devices when those could either simply be a PCI-e slot of their own, they could be mounted vertical instead of flatly, or mounted on the back of the board. They could eliminate the SATA and make those a bridge insert inside the m.2 to free up more board space as well, there's a lot that could be done to give us back our much needed PCI-e slots. But it doesn't happen.

I'm 100% with you.

Too many MoBo makers are designing modern MoBo's via Pure Aesthetics First, Functionality LAST.

It's asinine and Ass-Backwards.

Nobody needs all the fancy looks & colors.

We need Maximum Connectivity, Minimum Color-Fullness & Decorative Heatsinks.

NoBody asked for M.2 to be used outside of "Note Books".

I wanted the old 1.8" HDD Form Factor to be re-purposed to be the new SSD format.

















































I want to decide what type of Drives I want to connect, stop wasting MoBo Vendor's SKU's with minor variations based on Connector Options.

"Less is More", we need to move to a world based off Mini-SAS HD connectors using U.3 / U.4 that allows 100% backwards compatibility with SATA/SAS/nVME over PCIe/PCIe connections.

Li Ken-un said:

Let’s assume your last claim is true. Then here’s the reason:
There are two ports, each capable of minimum 64 gbps PCIe traffic bidirectionally, making the combination capable of 128 gbps. The connection on the host side being PCIe Gen 4 \00d7 4 caps the bandwidth of both combined ports to 64 gbps.
So the only way to utilize the full Thunderbolt bandwidth is to dedicate one port to video or to use both ports for both video and data.Intel’s implementation has a two-to-one host-to-port PCIe bandwidth ratio.

ASMedia’s implementation of USB4 (off-brand Thunderbolt 4) also has two ports, but at half the bandwidth, and yet the host side is PCIe Gen 4 \00d7 4. This design choice makes it possible to use at least 32 gbps of PCIe bandwidth for each port without any video traffic, thereby affording users a choice of how to allocate their port bandwidth.

ASMedia is still developing their USB4 v2.0 implementation, so it’s unfortunate that Intel’s video-first implementation is the one and only game in town. But by analogy, they would have to be using a PCIe Gen 5 interface on the host side and possibly also on the device side.


Now, this second part is more speculative, but:
Circumstantial evidence points to USB4 being actually capable of 40 gbps PCIe bandwidth if both the host and device side use PCIe Gen 4 \00d7 4. Because this is just what ASMedia did for their USB4 chips for devices (e.g., the chip that goes into the external SSD enclosure). How would PCIe Gen 4 \00d7 4 make sense unless the designers knew it was possible to surpass 32 gbps of PCIe bandwidth per Thunderbolt connection?
The PS2251-21 USB4 NAND flash controller from Phison claims a 4,000 MB/s rate. That would be impossible if PCIe data were capped to 32 gbps out of a total 40 gbps becuase of PCIe and USB/Thunderbolt overhead. I’m no stranger to <Mod Edit> marketing claims―especially product listings which advertise theoretically impossible speeds because they are also counting the protocol overhead as part of the useful payload of data being transmitted. Thus, I was surprised to find this Kickstarter which shows a USB4 external storage device breaking past even 4,000 MB/s:
That Kickstarter project is the one and only example I could find, so I’m taking it with a grain of salt. But taken together, it’s compelling evidence that 32 gbps is theoretically not the PCIe bandwidth cap for USB4/Thunderbolt 4 and 64 gbps won’t be the cap for USB4 v2.0/Thunderbolt 5.


Finally, I’m going to admit I am a bit uncertain about the technical capabilities of USB4 v2.0/Thunderbolt 5’s assymetrical mode of operation. All the marketing materials thus far use one-way video transmission as the application for this capability. But that doesn’t necessarily mean it can only be used for video.

This had been my (any many others’) mistake in understanding USB4/Thunderbolt 4’s capabilities years ago. I thought PCIe bandwidth was capped at 22 gbps or so after subtracting video’s exclusive share of the 40 gbps. Many tests were able to experimentally verify and no counterexamples existed. But that was also because Intel’s implementation was the only game in town. Only when ASMedia’s USB4 implementation became available were we proven wrong.

I hope we’re all wrong thinking that video traffic gets dibs on 120 gbps of asymmetrical bandwidth and that the 120 gbps is only outgoing (from the host). Because why would such a feature not be useful for reading or writing a lot of data to an external SSD or loading tensors to eGPU VRAM?


Anyhow, my whole point has been: I hate Intel’s implementation, which continues a long tradition of crappy implementations, and I hope ASMedia fully fulfills what is technically possible for USB4 v2.0.

You wrote a lot of words to say: you don't know what the Thunderbolt spec is and can't be bothered to look it up... Intel sets the specification for TB period. USB4 is based on TB, but is it's own specification so I would expect devices using USB to work at a higher rate since it doesn't use PCIe tunneling for data.

https://www.anandtech.com/show/20050/intel-unveils-barlow-ridge-thunderbolt-5-controllers
edit: Also without a PCIe switch you're not going to be able to convert PCIe 5.0 x4 into 2x PCIe 4.0 x4 (TB uses PCIe for data) which would probably double if not triple the cost of the card if there's even a switch that small available for PCIe 5.0. This is of course assuming that would even be possible with a single TB controller and if not you'd need two of those as well.

thestryker said:

Also without a PCIe switch you're not going to be able to convert PCIe 5.0 x4 into 2x PCIe 4.0 x4 (TB uses PCIe for data) which would probably double if not triple the cost of the card if there's even a switch that small available for PCIe 5.0. This is of course assuming that would even be possible with a single TB controller and if not you'd need two of those as well.

ASMedia’s controller does just fine using a PCIe Gen 4 \00d7 4 host interface to support USB4/Thunderbolt 4. What doesn’t translate to a PCIe Gen 5 \00d7 4 host interface supporting USB4 v2.0/Thunderbolt 5?

thestryker said:

Intel sets the specification for TB period.

Except that Kickstarter page I linked also shows a 12th Gen Intel mobile CPU being capable of over 32 gbps PCIe bandwidth:

So Intel’s CPUs with Thunderbolt built in can blow past 32 gbps. Since it’s Intel’s baby, it surely is Thunderbolt.

Also, ASMedia’s USB4® Device Silicon Has Passed Thunderbolt™ 4 Certification.

So my original statement hasn’t refuted:

Li Ken-un said:

Intel just can’t stop making crappy Thunderbolt controllers…

I laid out my points with information I could gather. It’s empirical/circumstantial, but all of it points to Intel’s Thunderbolt chips being deficient in PCIe bandwidth capabilities.

All of this implies that the Thunderbolt 4 spec has nothing to do with such limitations.

thestryker said:

You wrote a lot of words to say: you don't know what the Thunderbolt spec is and can't be bothered to look it up...

Li Ken-un said:

ASMedia’s controller does just fine using a PCIe Gen 4 \00d7 4 host interface to support USB4/Thunderbolt 4. What doesn’t translate to a PCIe Gen 5 \00d7 4 host interface supporting USB4 v2.0/Thunderbolt 5?

Having a higher speed interface doesn't change how the controller works, perhaps in your original post you meant the controller should be PCIe 5.0 not the card? If so then we were both talking about two different things.

Controller PCIe interface wise they can use whatever they want to, but maximum speeds are limited by the design of the protocols themselves. In other words if your goal was getting maximum speed across two ports then yes PCIe 4.0 based controller would be able to do that.

Li Ken-un said:

Except that Kickstarter page I linked also shows a 12th Gen Intel mobile CPU being capable of over 32 gbps PCIe bandwidth:
So Intel’s CPUs with Thunderbolt built in can blow past 32 gbps. Since it’s Intel’s baby, it surely is Thunderbolt.

Those results, if they're even to be believed in the first place, are on laptops which have integrated controllers that aren't connected by PCIe. In the case of Intel the links are separated so they get maximum bandwidth possible with the only limit being the protocol not the interface which should mean exactly 32Gbps (4GB/s) for data. I'm not as familiar with AMD's design, but as far as I'm aware they integrate their USB controllers into the silicon for laptop SoCs so they should act identically to Intel's.

Li Ken-un said:

Also, ASMedia’s USB4® Device Silicon Has Passed Thunderbolt™ 4 Certification.

This isn't a host controller it's a device controller.

Li Ken-un said:

I laid out my points with information I could gather. It’s empirical/circumstantial, but all of it points to Intel’s Thunderbolt chips being deficient in PCIe bandwidth capabilities.

TB3 controllers shared everything which is what caused the low transfer rates which was somewhat fixed with the TB4 controllers, but Intel's initial ones were PCIe 3.0 so that still limited the maximum bandwidth to the controller. ASMedia's host solution came out a couple of years after Intel's first TB4 host controller and used PCIe 4.0 which eliminates that bottleneck. Due to the extra bandwidth this controller could act a lot more like the integrated implementations in laptop SoCs.

Intel didn't bother releasing another TB4 controller until the TB5 controllers (~4 years apart), but this one does use PCIe 4.0 so I imagine it too will perform much like integrated.

I assume the reason they didn't go PCIe 5.0 for the new controller is that there aren't extra PCIe 5.0 lanes on any Intel client platforms. There's no reason to design a controller for use with an interface that simply doesn't exist.

What are thunderbolt headers for? Is it only compatible with specific Gigabyte motherboards, like for the USB4 ASM4242 (Asus/MSI) add-in card, or with any motherboard with generic pcie 4.0 slots?