UPDATE: Intel confirmed it referenced USB 3.1 in the presentation, meaning Thunderbolt 4 is in fact not faster than Thunderbolt 3. We updated the text accordingly.
Intel's press conference at CES 2020 last night was underwhelming given its lack of hardware announcements, but the company did partially pull the covers off of its new Tiger Lake processors and included vague slides that touted a "new" integrated Thunderbolt 4 connection. Given this is the first mention of the new interface, it has generated quite a bit of interest.
However, we followed up with a well-placed industry source who claims Thunderbolt 4 isn't new at all: It is largely an Intel re-branding campaign that signifies both the USB 4 and Thunderbolt 3 connections have been fully certified by Intel. That means this connection is not faster than the existing interface.
We followed up with Intel, which initially provided this response:
"Thunderbolt 4 continues Intel leadership in providing exceptional performance, ease of use and quality for USB-C connector-based products. It standardizes PC platform requirements and adds the latest Thunderbolt innovations. Thunderbolt 4 is based on open standards and is backwards compatible with Thunderbolt 3. We will have more details to share about Thunderbolt 4 at a later date."
The statement does reference "the latest Thunderbolt enhancements," but doesn't clarify if the interface is faster than Thunderbolt 3, which means there could be some new manageability features that Intel deems are worthy of a new badge. The protocol will also now ride on the new PCIe 4.0 interface, and although that doesn't mean it will be faster, it may serve as the impetus to update the branding. We asked Intel if Thunderbolt 4 is faster than Thunderbolt 3, to which the company responded "more details to come at a later date."
However, in response to a clarifying question on which USB protocol Intel referenced in its presentation, the company confirmed the it referenced USB 3.1, which means Thunderbolt 4 is in fact not faster than Thunderbolt 3.
At the end of the day, the implication is very simple: Thunderbolt 4 is not faster than Thunderbolt 3 but comes with a new name and a new badge and perhaps a few new features.
Intel donated the Thunderbolt 3 protocol to the USB standards committee last year to further the adoption of the spec, and the committee summarily rolled it into the new USB 4 spec.
|Specification||Throughput||Technical Term||Marketing Term|
|USB 4||40 Gbps||USB 4.0||Not Announced|
|USB 3.2||20 Gbps||USB 3.2 Gen 2x2||SuperSpeed USB 20Gbps|
|USB 3.1||10 Gbps||USB 3.2 Gen 2||SuperSpeed USB 10Gbps|
|USB 3.0||5 Gbps||USB 3.2 Gen 1||SuperSpeed USB|
The USB-IF committee has received plenty of criticism for its confusing naming schemes, and decoding Intel's reference to the USB3 standard was difficult because it didn't specify the version referenced. After further clarification, Intel referenced USB 3.1, which you can see reaches up to 10 Gbps, making Thunderbolt 4 throughput the same as Thunderbolt 3. You can see further details of the specification here.
While Intel donated the Thunderbolt 3 specification to the USB-IF committee, which allows anyone to produce Thunderbolt 3-supporting silicon without a fee, the chips still require certification if they want to earn the Thunderbolt badge, and that's where Intel steps in to generate some revenue.
Manufacturers of end devices pay a one-time fee for the certification, which is the only payment required to obtain the Thunderbolt 3 badge, but cable makers also have to pay a fee for the badge and are subject to ongoing rigorous inspections that include spot checks and factory audits to ensure that quality remains acceptable on an ongoing basis. Intel also hosts plugfests, during which interoperability with numerous new devices is tested, and workshops.
Now Intel allegedly also wants to make sure that the USB 4 side of the equation is also certified, which will naturally require a fee for the process, and manufacturers that earn Intel's certification for both USB 4 and Thunderbolt 3 will purportedly step up to the new branding tier: Thunderbolt 4.
With no bandwidth improvements and perhaps few new features, it seems like Thunderbolt 4 is largely Intel slapping on a branding badge and adding certification fees on the industry-standard USB4 interface and its newly-donated Thunderbolt 3 specification.
The slide also touts the "new integrated Thunderbolt 4," which might reference some new level of Thunderbolt 3 integration inside the chip. Intel already introduced this type of arrangement with the Ice Lake chips, but we'll have to wait to see if there are substantive changes to the implementation.
Intel originally certainly didn't provide much clarity on the development, as the only mention of Thunderbolt 4 came during the closing lines of the press conference, in which Gregory Bryant said:
"We're doubling the graphics performance generation on generation, industry-leading AI performance, integrated Wi-Fi 6, integrated Thunderbolt 4 for the first time, that's just about it."
Without any more details from Intel on the matter coming any time soon, it's hard to determine just what new features Intel deems as worthy of a new badge.