Thunderbolt 5: Only Necessary for the Most Demanding Uses
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-rate 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 up to 6.6 feet (2 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 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.
Ultimately, people need to stop referring to the version numbers of the USB standard documents when referring to various data rates. The USB forum itself tells people to not do that and instead use buzzwords that directly describe the data rate.
According to their current marketing name guidance document, device makers should call their ports:
depending on the ports’ actual capabilities.
I don’t get it: Why can’t Apple make a real pro computer with a decent and fast NVME-slot-disk?
So good that we’ve standardized on one port.
It’s technically possible, we know that. Hardware encryption keys and FV could be used to allow/continue pairing (that’s how Apple itself swaps bad flash on Mac Pro and Studio) to ensure a malicious actor can’t just pop open your Studio or Mac Pro and take it to read it out back at the bad guy lab. We know performance wise this works and we know the hardware is there as Apple itself slots their flash on the Studio and Mac Pro, paired albeit which is what prevents you from just using any flash in there.
It’s very hard to make a decent case at this point that it’s not just about being much better business for Apple not to offer that. As soon as that slot is in there, others are going to try to offer flash for it and with the Right to Repair push, it’s clear they wouldn’t be able to fend them off indefinitely. It’s much better business for them to not offer any such expansion and instead force people to configure their Macs with expensive flash options as BTO at order time. Even better, when people have to buy a new Mac from them (and perhaps resell/trade in the old) when they need/want to expand their fast internal flash.
It’s very hard to imagine Apple could make nearly as much “free” profit if they offered slotted flash on systems like the Studio or Mac Pro. It’s not a satisfying reason, but on the next-quarter horizon of the narrow-minded money and market people, this would appear to make sense. Who needs happy and loyal customers when you can juice up your next quarterlies with what is essentially free money?
My guess would be because, like the iPhone mini, basically no one uses it.
I think this otherwise excellent article gives short shrift to one advantage for Thunderbolt 5 use by regular computer users: storage for apps and files at near-internal drive speeds.
I’ve been trying to decide whether to upgrade the family 2017 iMac (with a mostly-filled 4Tb Fusion Drive that died and is being booted from an external TB3 4Tb SSD) with either a new M4 iMac or a new M4 Pro Mac Mini.
Because of our additional storage needs, and the number of apps which will have to now be installed on an external drive, the TB5 port in the mini is very compelling so as to get the fastest speed for apps and files from the external drive that will be needed.
While something like OWC’s TB3 Envoy Pro ($550) offers up to 2800 MB/s speed, their new preorder Envoy Ultra ($600), one of the first available external Thunderbolt 5 SSD drives, is up to twice as fast as USB4/TB4, and approaches the speed of an internal SSD from Apple (which charges a chucklesome $1200 to upgrade from the 512Gb base SSD).
More, Thunderbolt 5 offers excellent future-proofing in the event that one’s internal SSD malfunctions. Prices for Thunderbolt 5 drives will go down in time, so being able to eventually purchase a more affordable external to use as a boot drive clone backup means that one can get back to work fast if the mini’s internal storage suddenly dies.
Indeed, that’s what we’re doing right now with this old Intel iMac, whose 4Tb Fusion Drive started throwing off errors during the pandemic. The external Samsung USB3 SSD we’ve been using for a few years isn’t that bad in use as our boot drive, but it’s not ideal, not recommended for dealing with large audio files in Ableton, and not nearly as fast as a Thunderbolt 5 would be.
For simplicity’s sake I’d prefer to buy an iMac, but Thunderbolt 5 is the one feature in the mini that has me leaning towards it.
I don’t think for most people, which the article defines in some detail, having external 8,000 MB/s SSD storage is a key necessary compared to, say, 2,800 MB/s or even 4,000 MB/s. It’s definitely an issue for some people, and those people are enumerated in the piece.
I have a RAID0 7200 rpm hard drive setup for “offline” stuff (mostly backing things up and recording video from a DVR). It works great and is fairly cheap! I use USB 20 Gbps drives for most external storage.
Curious about this. Is that just the drive rating? I’m not aware of any Mac that can actually push 20 Gbps over its USB-C ports. If it’s not TB, I though the fastest USB any Mac would support is 10 Gbps.
Correct. These are SATA drives, so the actual performance is much lower. My point is that these suffice for nearly all my purposes. I’ve got the high-speed internal drive, reasonably fast USB 3.x drives (affordable), and relatively slow mirrored HDR and it suffices for all my photo editing, video editing, audio editing, and other CPU/GPU-heavy tasks. People who do this day in, day out on bigger projects are the ones who will benefit from Thunderbolt 5, as I note in the article.
Two reasons lots of users want to move away from HDDs for their non-backups usage is noise and power use. Noise on a HDD raid array is typically quite loud, and power use is relatively heavy too.
Unfortunately no company has released a multi-nvme box (say 4+ drives) that’s worth using at an affordable price. Mainly due to the still relatively unaffordable nature of >8TB nvme SSDs (the few 8TB ones available actually went UP in price significantly over the last 12mths), but also as cooling even slower nvme’s passively seems to be an issue when several are next to each other in the same box.
The only multi-drive unit I know about is the Iodyne one with several TB4 ports aimed at use for super-fast (and rich, lol!) video editors. So one has to wonder when this ‘all SSD’ future is coming (outside of mass backups and datacentres)…?
…in the meantime, you have those Nand updates for Mac Studios (likely Minis in near future) being offered on Kickstarter for a third the price of Apple’s prices.
I’m sure lots of people may be interested in beating Apple’s storage pricing strategy by availing themselves of those, lol!
What does all this mean for the current Apple displays? Both are equipped with Thunderbolt 3.
I don’t think anything really. They will work just fine attached to TB5 Macs, just as before they worked perfectly with TB4 Macs.
They should just work.
Thunderbolt is forward- and backward-compatible. You can plug any Thunderbolt (1, 2, 3, 4 or 5) device into any Thunderbolt computer and it will work. The two devices will negotiate to the highest bandwidth they both support.
The only “gotchas” are:
My MacBook Pro M4 Max is plugged into my TB4 caldigit doc and the two studio displays work just fine as suggested by others - wouldn’t have expected anything else :)
I think we should name things the same way hurricanes are named. We’re much better at remembering names like “Fred” or “Jane” than “USB27 9.6” or if “USB 120Pbps” also supports “USB 5Gbps”
Minor nit: 6.6 feet is 2 meters, not 3.
Up to a point. But I cite Apple’s use of names for macOS releases as a counterexample.
I usually need to consult a chart to know if Mojave came before or after Catalina, etc. I’d much rather just talk about macOS version 11, 12, 13, etc.
I guess it would work better if all the names were in lexicographic order by version (as they do with hurricane names in a given year). Ubuntu Linux does this, and I think it’s not a bad compromise between names and numbers.
Yep, just a typo that slipped through editing and is now fixed.
OWC has released their OWC Envoy Ultra external Thunderbolt 5 SSD drive. They’re claiming Real World performance of:
Thunderbolt 3 is only supported for Macs.
I’ve been waiting to see the specifications. I’m still waiting, because they don’t make any sense:
If this means that they cut and pasted the specs for some other product, then do we trust the system requirements?
If true, that means I couldn’t connect it to my Intel Mac with TB 3 ports that tops out at macOS 13 Ventura.
(I want to buy a second external SSD now because I’m currently running booted off of my external SSD backup drive. But after I replace the iMac next year, then I’d be able to take advantage of TB 5. This drive won’t work for that plan if I can’t connect it.)
This sounds weird to me. They say so in several places on the product page, but I don’t understand why a drive can or should know or care about what it is connected to. I wonder if this is a case of “unsupported” or “incompatible”.
They also say that it can only be a boot device on Macs. Again, I don’t understand. Bootability on a PC should depend on the PC’s ROM BIOS/EFI firmware. I would think that some will work and some will not. But maybe this is another case of “unsupported” so they don’t have to deal with BIOS configuration that will vary greatly depending on the motherboard used.
Agreed. Those specs make no sense. Definitely content that belongs with some other device. It looks like these specs are for some kind of docking station, not for an external storage device.
This may also explain the TB3 support restriction. If those specs are meant for a dock with three downstream ports, then it would make sense that TB3 will either not work or have limitations.
I contacted OWC about the Envoy Ultra spec page. They fixed the capacity and removed the downstream ports and DisplayPort info, but the system requirements remain the same.
Yeah, and they still make no sense. Like saying that only APFS is supported on Macs or that only macOS 14 and later is supported (and only 15 on Intel Macs).
If these are real technical requirements and not just a statement about what they’re supporting, then there’s something really weird going on in this device.
Note that an Apple Silicon Mac will not boot without a working internal SSD. When booting from an external, it first boots into the internal, then boots from external.
True. But yhe 6-7 years since macOS required handshaking from the internal T-series security hardware/firmware hasn’t shown to be a problem for users – unless the internal SSD fails. And if that happens you’d be in trouble regardless of which drive is your boot drive.
OWC has a useful article about Thunderbolt compatibility. The short story is that it’s not a big deal on the Mac, but is messier on Windows.
Interesting how TB4/5 peripherals aren’t compatible with TB1/2 hosts, even with an adapter. I wonder what the reason might be. I could understand power delivery issues, since Apple’s adapter doesn’t provide power, but I’m truly surprised that a device with its own power supply (e.g. a storage array) isn’t compatible.
Sounds like the promise of Thunderbolt 5 remains a promise for the most part.
Howard’s article is, as usual, excellent.
He points out an interesting macOS file caching behavior that can lead astray. Even using his own highly customizable Stibium, he was able to make it appear as if a M4P mini could over TB5 read 6 GB/s when in fact it really was doing much closer to 3.7 GB/s. But properly measuring that required unmounting/mounting a drive and restarting his tool to get macOS to flush the caches. I seriously hope OWC didn’t fall into that same trap. They happen to be marketing their brand new Envoy Ultra as reaching that same mysterious 6 GB/s over TB5.
OTOH, since we know TB4/USB4 can push north of 3 GB/s real world to/from fast NVMe flash, it is not out of the question to expect TB5 to be able to double that, under good circumstances at least, considering it has a twice as wide PCIe pipe at its disposal for that.
And other great TB5 article by Howard Oakley. He explains why you never saw 40 Gbps to a TB3-attached disk, why although you’ll see 6GB/s with TB5, you’ll also never see the advertised 80 Gbps, and why the marketing hype around TB5’s “120 Gbps” will not lead to 12 GB/s to/from an SSD. He also clears up where TB5 will really shine: b/w between dock and Mac - provided it works stable and as intended (he has some question marks there).
I think, as with all new technology, the “version 1.0” products that are being released now will have problems. Some may be fixed by firmware updates, but I think we can expect that it will be a year or two before devices all live up to the promises from Intel and Apple.
My 2017 Intel iMac is booted from a OWC Envoy Express, connected to the iMac’s TB3 port. Yesterday I cloned it to an OWC Express 1M2, connected to a USB 3 hub, and booted from it to turn on FileVault. Since the iMac doesn’t have USB4, this connection is at USB 3.1 (max 10 Gb/s). Update: actually was USB 3.0 at 5 Gb/s.
Does this article explain why the Express 1M2 connected to USB 3.1 (claimed 900 MB/s real-world) seemed to be faster than the Envoy Express connected to TB3 (real-world 1,553 MB/s)?
If not actually faster than the Envoy Express, it was certainly fast enough. I was surprised.
I suppose it is possible it was just faster because at that point, FileVault wasn’t on! This Mac doesn’t have a T2 chip. There’s no hardware acceleration of encryption/decryption.
The overhead from FV2 on external flash is small, typically several %.
However, what we perceive as “seems fast” is tricky. For one, the feel of using an external volume depends on a lot more than just peak b/w (IOPS for example is pretty important for a boot volume), but also, and perhaps more importantly, without actual benchmarking, it’s very easy to deceive yourself. Something BTW Howard also points out in his latest article on performance tuning.
Next you’re going to tell me that when I swapped my audio cables for cables with active zirconium anti aerial resonance Tesla coils, I was just imagining the more holistic soundstage.
It wasn’t even booting connected at 10 Gb/s! I forgot that my USB hub is USB 3.0, not 3.1, so it was connected at 5 Gb/s.
I’ve since moved it to one of the iMac’s USB 3.1 ports.
I don’t know if you were imagining the improvement or not, but you certainly could have invested far less with the infamous tice clock.