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USB4 vs Thunderbolt 4: Which Should You Care About?

2/1/2026 · Connectivity · 6 min

USB4 vs Thunderbolt 4: Which Should You Care About?

TL;DR

  • USB4 and Thunderbolt 4 share the same USB-C connector and similar theoretical bandwidth, but real world compatibility and features differ.
  • Thunderbolt 4 guarantees stricter minimum requirements: 40 Gbps, dual 4K or single 8K support, PCIe tunneling, and certain dock features.
  • USB4 can offer 40 Gbps too, but only if the host and cable support the higher protocol variant. Entry level USB4 devices may run at 20 Gbps or lack PCIe tunneling.
  • Buy Thunderbolt 4 if you need consistent high bandwidth, external GPUs, or robust docks.
  • Buy USB4 if you want broadly compatible, often cheaper devices and do not need guaranteed PCIe support.

What are USB4 and Thunderbolt 4

  • USB4 is the evolution of the USB standard that folds in ideas from Thunderbolt 3. It defines tunneling and higher speeds but allows optional feature sets.
  • Thunderbolt 4 is Intel's certification that mandates a specific feature set built on top of the Thunderbolt protocol, with guaranteed minimums for performance and features.

Bandwidth and Real Speeds

  • Both standards can support up to 40 Gbps in their full implementations.
  • Many USB4 devices, especially early or low cost ones, may only implement 20 Gbps lanes or limited tunneling.
  • Measured throughput depends on host, device, and cable. Cheap or passive cables can limit you to 20 Gbps even if ports say USB4 or Thunderbolt.

Protocols and Tunneling

  • Thunderbolt 4 mandates support for PCIe tunneling, DisplayPort, and USB. That makes it reliable for external GPU enclosures and high end docks.
  • USB4 supports tunneling too, but PCIe tunneling is optional in the spec. If you need PCIe over cable, verify the device supports it.

Daisy Chaining, Hubs and Docks

  • Thunderbolt 4 supports reliable daisy chaining and full featured docks with multiple displays and PCIe devices.
  • USB4 docks are becoming common, but capabilities vary. Some docks act like multiport USB hubs rather than true TB4 docks.
  • If you expect a single cable to power a laptop, run multiple monitors, and connect fast NVMe storage, Thunderbolt 4 docks are the safer bet.

Cables and Connectors

  • Both use the USB-C connector. However not all USB-C cables are equal.
  • Look for active 40 Gbps cables for long runs or to maintain full bandwidth. Passive cables can work at 40 Gbps short lengths but may drop to 20 Gbps or 10 Gbps on longer runs.
  • When buying cables, check the advertised speed and whether the cable supports USB PD and Alternate Mode.

Power Delivery

  • Power delivery is separate from USB4 or Thunderbolt 4, but most TB4 docks and many USB4 devices support USB Power Delivery up to 100 W.
  • Confirm the dock or cable supports the wattage you need. Some small hubs only deliver 15 to 30 W, which may be insufficient for larger laptops.

Device and OS Support

  • Thunderbolt 4 devices tend to be certified and therefore more predictable across Windows and macOS.
  • USB4 support has improved in modern operating systems, but feature gaps can appear on older laptops or cheaper devices.
  • Macs with Apple silicon support Thunderbolt 4 features where Apple implements them, but compatibility still depends on the accessory.

Which Should You Care About?

  • Choose Thunderbolt 4 if you:
  • Need guaranteed 40 Gbps with PCIe tunneling for external GPUs or fast NVMe enclosures.
  • Want robust single cable docking with multiple monitors and guaranteed performance.
  • Prefer plug and play predictability across high end laptops.
  • Choose USB4 if you:
  • Want cheaper accessories and are mainly using external displays, storage, and standard peripherals.
  • Do not need guaranteed PCIe support or maximum rated bandwidth.
  • Are building a mixed ecosystem where broad compatibility is more important than top end throughput.

Buying Checklist

  • Confirm the port type on your laptop and the dock or cable rating.
  • For 40 Gbps, look for active 40 Gbps cables and explicit 40 Gbps support on both host and device.
  • If you need external GPU support or NVMe over cable, verify PCIe tunneling is supported.
  • Check power delivery rating of docks and cables if you want laptop charging.
  • Read reviews that measure real world throughput rather than relying solely on spec sheets.

Bottom Line

Thunderbolt 4 is the reliable, more strictly defined option for users who need top end performance, external GPUs, or premium docks. USB4 delivers many of the same benefits at a range of price points, but features and speeds can vary by implementation. Match the port, cable, and accessory features to your real world needs rather than the label alone.

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