Intel confirms Thunderbolt 5 name, 120Gbps tech arrives in 2024

Intel today confirmed key details about the next generation of Thunderbolt cable, Thunderbolt 5. The company expects PCs and accessories with Thunderbolt 5 to release in 2024.

Intel will release Thunderbolt 5 technical collateral and development resources to developers in Q4 of 2024, Jason Ziller, general manager of the client connectivity division at Intel, told reporters ahead of the announcement.

Thunderbolt 5: What’s the difference?

The main feature of the new specification is its ability to transmit data at up to 120 gigabits per second (Gbps) while simultaneously receiving data at up to 40 Gbps. The mode, which Intel is dubbing Bandwidth Boost, only occurs when a high-bandwidth display is connected.

An Intel spokesperson told Ars Technica that Intel's still finalizing the requirements for a display triggering Bandwidth Boost mode.

"The trigger point will be set at an optimal level to balance the overall transmit and receive bandwidth as the user needs more than 40Gbps of transmit bandwidth for display content," they said.

Otherwise, the default mode is 80Gbps out and 80Gbps in simultaneously (four 40Gbps logical lanes total). The default mode still offers twice the speed of Thunderbolt 4's 40Gbps.

Here's a broad overview, with some help from Intel, of how Thunderbolt 5 compares to other specifications using USB-C.

*Intel notes that this only refers to maximum theoretical numbers and that actual performance depends on the specific hardware and software configuration.

**Intel notes that this is available with support for up to 20Gbps.

Thunderbolt 5 will support previous versions of Thunderbolt and is based on the USB-IF USB4 Version 2.0, VESA DisplayPort 2.1, and PCI-SIG PCIe 4.0 (x4) specifications.

In a briefing with the press, Ziller confirmed the specification name as Thunderbolt 5. Ziller said Intel wanted to continue the "tradition of keeping the branding, and naming, and labeling as simple as possible." He added that since Thunderbolt 5 requirements are all mostly mandatory, users always know what they're getting, and "you don't have to explain different variations of the capabilities." The note brings to mind the USB-IF's oft-bewildering naming conventions for USB specifications and the recent recommendation to name USB-C products based on their speed (such as "USB 40Gbps").

However, one area where users will encounter different capabilities from one Thunderbolt 5 product to the next is power delivery, as 240 W is optional, compared to the 140 W requirement.

Thunderbolt 5 increases bandwidth by moving from pulse-amplitude modulation-2 (PAM-2) signaling technology to PAM-3, as supported by the USB4 Version 2.0 specification. With PAM-2, each clock cycle has one eye, or opening, providing a 0 or 1 bit, Ziller explained. PAM-3 has two eyes per clock cycle, enabling a little bit of a higher clock rate, he added.

PAM-3 also allows Thunderbolt 5 to run on the same USB-C connectors, motherboards, and passive cables up to 3.56 feet (1 m) as Thunderbolt 4. If you're using an earlier version of Thunderbolt, Thunderbolt 5 will automatically switch to PAM-2 signaling.

120Gbps mode

Thunderbolt 5's support for up to 120Gbps comes from the USB4 Version 2.0 spec and makes Thunderbolt 5 10-times faster than the original Thunderbolt that debuted in 2011. Because of the advanced capability, Intel is marketing the technology as "the best display experience on a single connector," claiming to outperform DisplayPort, a favorite among power users like gamers.

Dynamic display bandwidth management is supposed to enable a Thunderbolt 5 port to detect when a bandwidth-hungry display—such as a high-resolution HDR display or high refresh rate monitor—is connected. Then, it'll automatically switch to transmitting data at up to 120Gbps (across three lanes) and receiving data at up to 40Gbps (via one lane). That means that if you're connecting multiple displays with different resolutions, Thunderbolt will "effectively and efficiently manage all of that and only allocate the bandwidth that's needed for each display." Thunderbolt 4 "doesn't do that quite as effectively," the executive added, so sometimes bandwidth is over-allocated to a display, making things less efficient.

Increased efficiency allows for up to three DisplayPort display streams with Thunderbolt 5 versus two with the previous Thunderbolt generation.

Amid all these improvements, Intel expects Thunderbolt 4 and Thunderbolt 5 to co-exist for a couple of years, with mainstream users opting for the prior-gen solution and creators and gamers being early Thunderbolt 5 adopters. Workstation users are expected to fall next in line.

Creators can leverage Thunderbolt 5 speeds, Intel envisions, to graduate from a pair of 4K, 60 Hz monitors to a trio of 4K, 144 Hz displays or "multiple" 8K monitors, for example. These figures are theoretical but still help illustrate the type of workloads Thunderbolt 5 may end up being relegated to.

Creators could also use the technology to move large amounts of data. Ziller claimed creators' biggest pain point is spending hours at the computer archiving data.

"There's more and more video being shot in 8K and being edited in 4K [and] 6K," Ziller said.

Despite Thunderbolt 5's advancements, there are drives, like many PCIe 5.0 ones, that could exceed Thunderbolt 5's bandwidth.

Gamers, meanwhile, could hit a theoretical refresh rate of 540 Hz with Thunderbolt 5. Ziller also sees gamers moving to the next-gen tech for transporting large game libraries and for "studio-quality capture and streaming or archiving for future playback in real-time."

Thunderbolt 5 products

Intel expects Thunderbolt 5 to land on every category of device that currently offers Thunderbolt 4. The company seemed particularly excited about docking opportunities in various categories and form factors, from monitor stand docks to portable and commercial docks.

Intel's argues that a Thunderbolt 5 dock is preferrable to alternatives using multi-function modes. A spokesperson pointed to USB-C based docking solutions that "only support 10Gbps of USB data and use lossy compression to send video over a USB connection or are limited to one display stream and must split the video bandwidth to support multiple monitors resulting is lower quality and resolution."

Intel also thinks Thunderbolt 5 could enable external AI accelerators in the coming years. During the press briefing, Ziller pointed to "the push for AI in the clients over the next few years" instead of the cloud, for things like video collaboration, audio effects, creator and gamer effects, and local AI inferencing.

Intel also showed optimism about external GPUs (eGPUs) finally taking off with Thunderbolt 5, thanks to bandwidth doubling compared to Thunderbolt 4. Ziller pointed to Thunderbolt's use of the PCI bus as enhancing performance potential, including around frame rates and reduced export time for creators. eGPUs never really took off with Thunderbolt 4 or Thunderbolt 3, but Thunderbolt 5's boosted capabilities could enable vendors to attempt more competitive products.

Ziller wouldn't confirm if any discrete GPU manufacturers (like Intel) will implement Thunderbolt 5 beyond saying it is technically possible.

Intel said PC makers will be able to design computers with up to four Thunderbolt 5 ports. The executive also wouldn't confirm which CPU platforms might implement Thunderbolt 5. But Thunderbolt 5 runs on updated silicon via a discrete chip (codenamed Barlow Ridge). That means that, like with Thunderbolt 4, it would be technically feasible for non-Intel PCs, like ones running AMD or Arm, to support Thunderbolt 5. Intel doesn't charge royalties for Thunderbolt certification, but there are testing fees (paid to testing labs, not Intel) associated with Thunderbolt certification. USB4 Version 2.0 offers much of the same potential as Thunderbolt 5, so it's possible non-Intel systems will opt for the USB-IF specification when seeking similar functionality to Thunderbolt 5.

Ziller said Intel will be taking Thunderbolt 4-branded cables and putting them through additional validation testing for Thunderbolt 5. The cables are expected to pass, at which point they'll earn Thunderbolt 5 branding.

Active Thunderbolt 5 cables will take longer to arrive because they require a USB redriver change. But Intel expects passive Thunderbolt 5 cables to be up to 6.56 feet (2 m) long.

Next generation

Considering Thunderbolt 4 carried the same data transfer rates as Thunderbolt 3, Thunderbolt 5 represents a much more exciting evolution for Intel's technology. A simple naming convention may also simplify things when shopping for other types of USB-C products.

But we can also expect Thunderbolt 5 products to come at a premium price, especially during its first two years of release. With Thunderbolt 5's best feature limited to extreme types of displays, it will be years before Thunderbolt 5 becomes a necessity in many people's lives, if ever.

It's also unclear how well the dynamic bandwidth management will work. However, the transition should be seamless and effortless to ensure the feature's benefits are maximized and not a distraction. This is especially important since there doesn't seem to be a way to toggle modes manually.

But for power users looking toward more advanced display, storage, and graphics technologies, Thunderbolt 5 brings vast potential.

Editor's note: This article was updated with additional information from an Intel spokesperson.