Thunderbolt 5 vs Thunderbolt 4 vs USB4: What Changes on Your Desk

Most people need Thunderbolt 4, not Thunderbolt 5. A Thunderbolt 4 dock runs one or two ordinary 4K monitors, charges a typical laptop and works with Thunderbolt 5 laptops too. Thunderbolt 5 doubles the minimum link to 80 Gbps, adds a 120 Gbps Bandwidth Boost for monitors and doubles the PCIe data rate, but you only get that if the laptop, dock and cable all support it. USB4 shares Thunderbolt's plug and base standard with lower guaranteed minimums. For the full background, start with our guide to USB-C and Thunderbolt docking stations.

The short version

• Thunderbolt 5 vs Thunderbolt 4: Thunderbolt 5 doubles the PCIe data rate (64 Gbps against 32 Gbps), raises the required charging on a laptop port, and adds Bandwidth Boost for monitors. It matters most for very high-resolution screens, fast storage and 140W laptops.
• USB4 vs Thunderbolt 4: USB4 is the USB-IF standard that Thunderbolt is built on. Thunderbolt 4 is Intel's certified version with higher minimums, so a Thunderbolt 4 port is more predictable than a plain USB4 one.
• What is common: all three use the USB-C plug, and Thunderbolt products are designed to work with USB4 and USB 3 products.
• Most people can skip Thunderbolt 5 for now. A Thunderbolt 4 dock already runs two monitors on any laptop that supports two screens, and it works with a Thunderbolt 5 laptop at Thunderbolt 4 speed.

What is new in Thunderbolt 5

Thunderbolt 5 is built on USB4 version 2 and DisplayPort 2.1. The figures below come from Intel's Thunderbolt 5 technology brief and overview page. Four changes matter on a desk.

Bandwidth Boost for monitors

Thunderbolt 5 normally gives 80 Gbps in each direction. When a system needs more video bandwidth, Bandwidth Boost rebalances the link to 120 Gbps in one direction and 40 Gbps in the other. That is up to three times the video bandwidth of Thunderbolt 4, and up to 50% more than DisplayPort 2.1 (UHBR20). Bandwidth Boost is based on the asymmetry mode in the USB4 version 2 specification. It only helps if your monitors need it: a pair of ordinary 4K screens does not.

Twice the data rate for storage and networking

Thunderbolt 5 carries 64 Gbps of PCIe data against 32 Gbps for Thunderbolt 4, and Thunderbolt networking at 64 Gbps against 32 Gbps. USB 3 data stays at 10 Gbps as a requirement, with up to 20 Gbps available. You see the PCIe difference with fast external SSDs and RAID drives. CalDigit, for example, lists external storage on its Thunderbolt 5 dock at up to 6,200MB/s and on its Thunderbolt 4 dock at 3,200MB/s, both as maximums.

Higher charging requirements

A Thunderbolt 4 laptop must accept charging up to 100W on at least one port, with up to 140W available. For Thunderbolt 5 it is required up to 140W, with up to 240W available. Thunderbolt 5 supports, but does not require, Extended Power Range delivery of up to 240W through USB Power Delivery 3.1. In practice, the charging wattage of a dock still depends on the dock. CalDigit lists 98W for its Thunderbolt 4 dock and 140W for its Thunderbolt 5 dock.

A higher video minimum

The required PC video support is dual 4K for Thunderbolt 4 and dual 6K for Thunderbolt 5. Intel's later overview page markets Thunderbolt 5 as supporting dual 8K monitors, with display stream compression. These are the minimums the standard sets, not what any laptop delivers. The laptop still sets the number of screens: a hub or dock does not increase the maximum number of displays a Mac supports.

Thunderbolt 5 vs Thunderbolt 4: the requirements side by side

Source: Intel's Thunderbolt 5 technology brief (September 2023), which is Intel's own pre-launch summary. Our docking stations guide has the overall Thunderbolt and USB4 table, so this one only shows the rows where Thunderbolt 5 changes something.

USB4 vs Thunderbolt 4: same plug, different promises

USB4 is the USB Implementers Forum (USB-IF) standard. It is based on the Thunderbolt protocol specification that Intel contributed, it doubles the maximum aggregate bandwidth of USB, and it runs at up to 80 Gbps over 80 Gbps certified cables. A USB4 connection scales to the best mutual capability of the devices connected.

Thunderbolt 4 is Intel's version. Thunderbolt requires USB4 compliance, and Intel validates and certifies every product carrying the Thunderbolt logo. Intel's table lists a USB4 minimum of 20 Gbps for the PC, against 40 Gbps for Thunderbolt 4, and no PCIe requirement. So the practical difference for a desk is what is guaranteed. CalDigit notes that its docks' Ethernet works on Thunderbolt hosts but only on USB4 hosts that support PCIe, so check with the laptop maker before you pair a Thunderbolt dock with a USB4 laptop.

Naming: what the labels mean

USB-IF asks manufacturers to use plain speed names: USB 80Gbps, USB 40Gbps, USB 20Gbps, USB 10Gbps and USB 5Gbps. The terms USB4 Version 2.0 and USB4 Version 1.0 are not meant for product names or packaging. So a box that says "USB 80Gbps" means the product signals at 80 Gbps, and a "Thunderbolt 5" logo means Intel certified it. Look for the speed on the box, not just "USB-C".

Thunderbolt vs USB-C

USB-C is the plug, and Thunderbolt and USB4 are the ways to use it. Thunderbolt uses the same oval connector as USB-C, but its certification requires higher minimums for cables, PCs and accessories. A Thunderbolt dock still works on a laptop with plain USB-C, with fewer features: CalDigit lists one external display for its TS4 on a USB-C Windows laptop, for example.

The way a dock drives two screens matters on a Mac. Thunderbolt docks send each screen its own signal, which macOS handles. Many plain USB-C docks with two or three video outputs split one video signal with DisplayPort Multi-Stream Transport (MST) instead. Windows supports MST, but macOS does not support it for extended displays, so on a Mac those screens all show the same picture.

What changes on your desk

Docks

Thunderbolt 5 docks are built to use the extra bandwidth, so they only pay off if your laptop can use it too. CalDigit's TS5 needs an 80 Gbps Thunderbolt 5 or USB4 version 2 host connection for maximum performance, and it has a Thunderbolt 5 host port, three more Thunderbolt 5 ports and up to 140W of charging. Its Thunderbolt 4 TS4 has three Thunderbolt 4 ports and up to 98W. Plugable's Thunderbolt 4 TBT4-UDZ works with Thunderbolt 5, Thunderbolt 4, USB4 and USB-C laptops. You can see both in our guide to the best Thunderbolt docks for MacBook and Windows laptops.

Monitors

More bandwidth does not mean more monitors on its own. CalDigit lists three displays through its Thunderbolt 5 dock on an M5 Pro or M5 Max Mac and on Windows Thunderbolt 5 laptops that support it, and notes that Windows Thunderbolt 4 laptops cannot connect three displays natively. The Mac limit comes from the chip: Apple lists up to two external displays on a MacBook Pro with an M4, M4 Pro or M5 chip, three with an M5 Pro and four with an M5 Max. Base M1 and M2 Macs support one. For dual-screen setups, see our best dual monitor docking stations for laptops.

Storage

The extra PCIe bandwidth of Thunderbolt 5 helps with drives that are faster than a Thunderbolt 4 link can carry. Our best external SSDs guide covers drives; a drive that runs on 10 Gbps USB will not use the extra bandwidth.

Cables

The cable can decide what you get. The 80 Gbps USB speed needs 80 Gbps certified cables, and Thunderbolt 5 universal cables reach 120 Gbps at up to 2 meters. Intel's brief claims Thunderbolt 5 signaling works over passive cables, connectors and boards that previously supported 40 Gbps. CalDigit's advice is more cautious: certified 40 Gb/s Thunderbolt 4 cables for its TS4, and certified 80 Gb/s Thunderbolt 5 cables for its TS5. Use the cable in the box.

Which Macs have which port?

Apple lists Thunderbolt 5 on the Mac Studio from 2025, the 14-inch MacBook Pro with a Pro or Max chip from 2024, the 16-inch MacBook Pro from 2024 and the Mac mini with a Pro chip from 2024. Thunderbolt 4 is on MacBook Air from 2025, the 14-inch and 16-inch MacBook Pro from 2021 and the Mac mini from 2023. A port Apple calls Thunderbolt / USB 4 is on the MacBook Air from 2020 to 2024, the 13-inch MacBook Pro with M1 or M2 and the 14-inch MacBook Pro with M3, and Apple lists a single external display for it (a 2024 MacBook Air with M3 can run two with its lid closed). Apple's announcement of M4 Pro and M4 Max quoted Thunderbolt 5 at up to 120Gb/s, more than double Thunderbolt 4. To see what you have, use Apple's guide to identifying the ports on your Mac. Our MacBook Air vs MacBook Pro comparison covers the models themselves.

Do you need to upgrade?

• Keep your Thunderbolt 4 dock if you run one or two monitors and ordinary drives. It works with a Thunderbolt 5 laptop at Thunderbolt 4 speed.
• Look at Thunderbolt 5 if your laptop has a Thunderbolt 5 port and you run very high-resolution or high-refresh monitors, three or more screens, or fast external storage.
• Check the laptop before the dock. A Thunderbolt 5 dock on a Thunderbolt 4 or USB4 laptop runs at the speed the laptop supports. On Windows, Thunderbolt 5 needs Windows 11 version 23H2 or later.
• Do not buy on the plug. Two USB-C ports on one laptop can differ. Look for the Thunderbolt symbol, or the port speed in the spec sheet.
• On a Mac, avoid plain USB-C dual-monitor docks. Most use MST, so two screens mirror instead of extending.

How we compared

This comparison is research-based. We have not tested these standards, docks or cables ourselves, and every figure comes from the source linked under Sources. Most figures come from Intel, which owns the Thunderbolt name, so read them as the minimums the standard sets, not as what a given laptop delivers. We used four kinds of source: Intel's Thunderbolt documents, the USB-IF's USB4 page and naming guidelines, Apple's support pages for Mac ports and displays, and two dock makers' product pages for concrete examples. Where the sources disagree or leave a gap, we say so, and we did not research individual Windows laptops.