Originally published at: Thunderbolt 5: Only Necessary for the Most Demanding Uses - TidBITS
The first Thunderbolt 5 ports on Apple products appeared this week with the updated Mac mini and MacBook Pro models based on Apple’s new M4 Pro and M4 Max chips. (The plain M4 models use Thunderbolt 4.) Thunderbolt 5 expands on features introduced in previous releases and won’t make much of a difference until peripherals catch up. Even then, few people will truly need what Thunderbolt 5 offers, unlike the significant changes made several years ago with the move from Thunderbolt 2 to Thunderbolt 3.
Intel released the final Thunderbolt 5 specification in September 2023; the first peripherals and cables with Thunderbolt 5 appeared in August 2024. Apple is the first to incorporate Thunderbolt 5 into a computer.
Thunderbolt 5’s enhancements revolve around faster data rates, high-end video capabilities, and higher-wattage power delivery.
What’s New in Thunderbolt 5
Thunderbolt 5 can carry up to an aggregate of 160 Gbps, splitting that bandwidth in one of two ways. In typical usage, it will carry 80 Gbps of symmetrical data flow to and from a peripheral. However, it also supports a 120 Gbps/40 Gbps asymmetrical option for so-called “video-intensive” uses, which boils down to multiple high-resolution displays or displays with super-high refresh rates. (Refresh rates higher than the typical 60 hertz make moving images on a display appear more fluid and reduce blur—something desirable when watching sports, action movies, or playing games.)
Those video capabilities come as part of Thunderbolt 5’s support for DisplayPort 2.1, which can leverage up to 80 Gbps of data for single-display refresh rates as high as 240 Hz with 4K displays, support multiple 8K monitors at fast refresh rates, or drive a single 16K display at 60 Hz. With 120 Gbps, more displays at higher resolutions or refresh rates can be used.
Thunderbolt 5 also adds compatibility with 240-watt cabling and charging, meeting the USB Power Delivery (PD) 3.1 standard set in 2021. Apple created its own 240W charging variant over MagSafe 3 for the power-hungry 16-inch MacBook Pro, which requires 140W, because it came out before USB and Thunderbolt provided high-wattage support. (You can now use a Thunderbolt 5 cable to fast-charge the 16-inch MacBook Pro. In August 2024, Apple quietly released a $29 240W USB-C Charge Cable that’s $40 less than the company’s $69 Thunderbolt 5 Pro Cable.)
Finally, while Thunderbolt 4 supports USB4, Thunderbolt 5 supports USB4 2.0, which doubles USB4’s maximum data transfer rate from 40 Gbps to 80 Gbps, provides enhanced bandwidth allocation of up to 120 Gbps over three lanes, supports up to 240W power delivery, and offers DisplayPort 2.0 compatibility. (Yes, it’s called USB4 2.0, not USB5. We’re not responsible.)
| Feature | Thunderbolt 3 | Thunderbolt 4 | Thunderbolt 5 |
| Max data rate |
40/40 Gbps | 40/40 Gbps | 80/80 or 120/40 Gbps |
| Max power delivery | Under 15W or 100W | 100W in most cases | 240W option |
| USB level | USB 2, USB 3.1 or later | Plus USB4 | Plus USB4 2.0 |
That’s the nut: if you don’t need data rates over 40 Gbps or plan on using super-high-refresh or super-high-resolution displays, Thunderbolt 5 won’t make any difference in your life. That’s why Apple supports it only on the M4 Pro and M4 Max machines targeted at high-end professionals rather than the whole M4 lineup. Arguably, most of Thunderbolt 5’s features are aimed at capturing the vast amounts spent on high-margin, high-end goods by gamers, video editors, and others who want its performance and video capabilities. As today’s highest-performance SSDs and super-high-resolution displays drop in price, I expect more people will find Thunderbolt 5’s capabilities useful.
A Brief History of Thunderbolt
Thunderbolt 5 is the latest entry in an evolutionary tree that starts with Thunderbolt 3, the first version of the standard to use the USB-C connector type developed by the USB Implementors Forum (USB-IF). That group maintains the USB standard and is in a kind of cooperative war with Intel’s Thunderbolt. The USB-IF and Intel adopt and expand on each other’s improvements through open licensing and other principles that have enhanced both standards. I doubt we’d see this pace of improvement without this “co-opetition.”
Thunderbolt 3 provided a new baseline of 40 Gbps in each direction, though there were cabling issues. Thunderbolt 3 cables include circuitry that renders them either passive or active, which refers to the type of signaling chips built into the cables. Active cables are more expensive but can carry 40 Gbps at up to 6.6 feet (3 meters), whereas passive cables max out at 20 Gbps above 20 inches (0.5 m).
Only some Thunderbolt 3 cables had to carry up to 100W. Weirdly, any Thunderbolt 3 cable that allowed over 15W had to support up to 100W. There was also the problem that Thunderbolt 3 active cables throttled USB 3 to the older USB 2.0 data rate of 480 Mbps for complicated backward compatibility reasons. That’s why you could encounter Thunderbolt 3 cables that, when plugged into USB 3 on one end or the other, would provide unexpectedly poor data rates. You couldn’t look at a 15W or active cable and typically know what it was. (See, for instance, “How Some Thunderbolt 3 Cables Underperform with USB-only Drives,” 23 August 2017. Some charging-focused cables, like the Apple USB-C Charge Cable mentioned above, still only carry USB data at USB 2.0’s rate for complicated reasons.)
Thunderbolt 4 upgraded all the optional and “by-the-way” features in Thunderbolt 3 and made them mandatory. This included mostly ditching the active/passive cabling situation. All computers with Thunderbolt 4 must have at least one Thunderbolt port that provides 100W of power. Likewise, all Thunderbolt 4 cables must be capable of carrying 100W. All Thunderbolt 4 cables are active and must carry 40 Gbps at up to 6.6 feet when connected to capable devices on both ends.
When USB4 shipped—note the lack of a space in its name—it incorporated all the Thunderbolt 3 specs alongside backward compatibility with USB 2.0 and 3.x. This move allowed a single cable to support both Thunderbolt 4 and USB4! At last! (The only oddity is that some cables over about 32 inches (0.8 m) max out at 20 Gbps with USB4.)
After the awkwardly named USB-IF update to USB4, called USB4 2.0, was announced in September 2022, Intel came out with its own news about Thunderbolt 5 (then called “next-generation Thunderbolt”) in October 2022. USB4 2.0 was released as a specification to the industry in June 2023, and Thunderbolt 5 followed in September 2023. As you may have noticed above, Thunderbolt 5’s data transfer and power delivery specs sound a lot like USB4 2.0’s specs—in fact, Thunderbolt 5 adopted those specs from USB4 2.0.
Yes, that’s right. Despite Intel’s 2022 press release titled “Intel Leads Industry with Next-Generation Thunderbolt,” Thunderbolt 5’s improvements boil down to incorporating USB4 2.0—announced just before Thunderbolt 5 in October 2022—and DisplayPort 2.1.
Glenn Fleishman is the author of Take Control of Untangling Connections, a comprehensive guide that elaborates on the above standards. The book primarily focuses on assisting you in selecting the best hardware, peripherals, and cables to achieve optimal results while also addressing issues related to incompatibilities and slow data rates.
