USB4: The Most Capable — and Most Confusing — USB Standard Yet
USB4 has been rolling out across laptops, hubs, and peripherals for the past couple of years, but many people still aren't clear on what it actually offers — or how it differs from Thunderbolt 4, USB 3.2, and all the other standards that came before it. Let's sort it out once and for all.
What Is USB4?
USB4 is the latest generation of the Universal Serial Bus specification, developed by the USB Implementers Forum (USB-IF). It was designed to unify the fragmented USB landscape, incorporating the Thunderbolt 3 protocol and dramatically increasing bandwidth compared to USB 3.x.
All USB4 connections use the reversible USB-C connector — there are no USB4 Type-A ports.
USB4 Speed Tiers
This is where things get complicated. USB4 comes in multiple speed grades:
| Standard | Max Bandwidth | Notes |
|---|---|---|
| USB4 Gen 2×2 | 20 Gbps | Entry-level USB4 |
| USB4 Gen 3×2 | 40 Gbps | Matches Thunderbolt 4 |
| USB4 Version 2 | 80 Gbps | Latest spec; requires new cables |
The key takeaway: not all USB4 ports are equal. A device labeled "USB4" might only support 20 Gbps, so always check the spec sheet when buying devices or cables.
How Does USB4 Compare to Thunderbolt 4?
Thunderbolt 4 (Intel's proprietary standard) requires a minimum of 40 Gbps, dual 4K display support, and PCIe tunneling — making it more strictly defined than USB4. USB4 at 40 Gbps is electrically compatible with Thunderbolt 4, meaning Thunderbolt 4 devices generally work in USB4 40Gbps ports, but with potential feature limitations.
In short: Thunderbolt 4 ⊂ USB4 at 40 Gbps, but USB4 has more variation in what manufacturers can implement.
What Can USB4 Actually Do?
- High-speed data transfer: Move large files to NVMe SSDs at near-full drive speed.
- Video output: Drive one or two external displays (depending on port and device support).
- Power delivery: Supports USB Power Delivery (USB PD) up to 240W with the right cable and charger.
- Daisy chaining: Connect multiple devices through a single port using compatible hubs and docks.
- eGPU support: Connect an external GPU enclosure for boosted graphics performance on laptops.
Which Devices Support USB4?
USB4 is now appearing across a broad range of devices:
- Laptops: Most 2023+ laptops from Apple, Dell, HP, Lenovo, and ASUS include at least one USB4 port.
- Desktops: High-end desktop motherboards from Intel (12th gen+) and AMD (Ryzen 7000+) include USB4 on select boards.
- Hubs and docks: Several dock manufacturers now offer USB4-certified docks, unlocking the full bandwidth for connected peripherals.
- External SSDs: Next-gen portable SSDs from brands like Samsung and Western Digital are beginning to leverage USB4's speed ceiling.
Do You Need USB4 Right Now?
For most users, existing USB 3.2 or Thunderbolt 3 setups are still more than adequate. USB4 becomes relevant if you:
- Regularly transfer very large files (video, RAW photo archives) to external drives
- Run multiple high-resolution external monitors from a laptop
- Use or plan to use an eGPU
- Want a future-proof port configuration for your next device purchase
If you're buying a new laptop today, having at least one USB4 port is a smart future-proofing decision — even if you don't use its full capabilities immediately.