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USB-C vs Thunderbolt: Which Cable Should You Buy?

9/20/2025 · Connectivity · 8 min

USB-C vs Thunderbolt: Which Cable Should You Buy?

TL;DR

  • USB-C usually refers to the connector and a family of protocols. It can handle USB 2.0 up to USB4, and supports Power Delivery and Alternate Modes like DisplayPort.
  • Thunderbolt is a faster protocol that uses the USB-C connector in modern versions. Thunderbolt 3 and 4 can carry PCIe, multiple 4K displays, and up to 40 Gbps.
  • Short recommendations:
  • Buy Thunderbolt if you need maximum bandwidth, eGPUs, multi-monitor docks, or fast external NVMe without bandwidth bottlenecks.
  • Buy USB-C if you just need charging, basic peripherals, single 4K or 1440p display support, or a lower-cost cable.

Bandwidth and Versions

  • USB 2.0/3.2 Gen 1/Gen 2: 480 Mbps up to 10 Gbps for common USB-C devices.
  • USB 3.2 Gen 2x2: Up to 20 Gbps, rare on laptops.
  • USB4: Based on Thunderbolt 3 specs, can be 20 Gbps or 40 Gbps depending on implementation.
  • Thunderbolt 3/4: Up to 40 Gbps consistently. Thunderbolt 4 mandates minimal features like dual 4K or single 8K support and full PCIe tunneling.

Video and Displays

  • USB-C with DisplayPort Alt Mode: Can drive one 4K 60 Hz display or 1440p at high refresh depending on lane configuration.
  • Thunderbolt: Can handle two 4K 60 Hz displays or one 8K display over a single port at up to 40 Gbps.
  • If your laptop advertises USB4 or Thunderbolt, you get the best display flexibility.

Charging and Power Delivery

  • USB Power Delivery (PD): Negotiates voltage and current up to 240 W with USB PD 3.1 Extended Power Range, but most laptops use 45-100 W.
  • Thunderbolt ports commonly support PD, but the actual wattage depends on the host and charger.
  • Check the device specs for supported wattage rather than assuming full PD capability.

Cables and Connectors

  • Passive USB-C cables: Good for USB 2.0 and USB 3.2 up to 20 Gbps at short lengths.
  • Active cables: Required for full 40 Gbps over longer lengths and for some Thunderbolt use cases.
  • Look for labels: \"Thunderbolt\" icon or \"40 Gbps\" marking ensures full Thunderbolt bandwidth. Plain USB-C markings may indicate limited speeds.

Compatibility and Platform Notes

  • Macs: Recent Macs have broad Thunderbolt support. Apple uses Thunderbolt/USB4 on newer models.
  • Windows laptops: Thunderbolt support varies by model. Some USB-C ports lack Thunderbolt but still provide PD and DisplayPort Alt Mode.
  • Peripherals: A Thunderbolt device will often fall back to USB when connected to a non-Thunderbolt USB-C port, but features like PCIe tunneling or full speed may be lost.

Docks, Hubs, and Daisy-chaining

  • Thunderbolt docks: Provide multiple displays, fast storage, Ethernet, and charging with minimal bandwidth limits.
  • USB-C hubs: Great for adding ports but may split bandwidth across devices.
  • Daisy-chaining: Supported on Thunderbolt for multiple devices on a single port. USB-C does not offer the same daisy-chain capabilities unless through DisplayPort MST on some hosts.

Real world performance and limitations

  • External NVMe enclosures: Thunderbolt offers near-native speed. USB-C enclosures depend on the underlying USB or USB4 implementation and may be limited to 10-20 Gbps.
  • Docking scenarios: If you plan to run multiple high resolution displays and fast storage from one port, Thunderbolt docks give more headroom.

Which Should You Buy?

  • Choose Thunderbolt if:
  • You need high bandwidth for external GPUs, fast NVMe, or multiple 4K displays.
  • You want a single-cable dock that charges and connects many peripherals with minimal compromise.
  • Choose USB-C if:
  • You only need charging, pairing a single monitor, or plugging in keyboards and mice.
  • You want a lower cost cable or hub and do not need full 40 Gbps bandwidth.

Buying Checklist

  • Check device port type: Look for \"Thunderbolt\" icon or \"USB4\" label.
  • Cable rating: Buy active 40 Gbps cables for long Thunderbolt runs; passive cables are fine for short USB 3.2 uses.
  • Power needs: Confirm PD wattage for your laptop.
  • Display needs: Confirm DP Alt Mode or Thunderbolt support for required resolution and refresh.
  • Docks: Choose Thunderbolt docks for multi-4K setups or heavy storage use.

Bottom Line

USB-C describes a versatile connector and a range of protocols. Thunderbolt is the higher performance option that uses the USB-C shape in modern gear. If you need top bandwidth and the flexibility of a single high-performance dock, choose Thunderbolt. If your needs are modest, a good USB-C cable or hub will save money while covering charging and basic display duties.

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