USB-C 2.1, DisplayPort Alt Mode and Thunderbolt 5 Explained: Bandwidth, Power Delivery and Monitor Support

🏷️Technology
⏱️22 min read
📅2025-01-01

USB-C 2.1, DisplayPort Alt Mode and Thunderbolt 5 Explained

USB-C has become the universal connector, but the underlying protocols vary drastically.
A single USB-C port may support:

  • USB 2.0
  • USB 3.2
  • USB4
  • DisplayPort Alt Mode
  • Thunderbolt 3/4/5
  • Power Delivery up to 240W

This guide breaks down the differences between USB-C 2.1, DisplayPort Alt Mode and Thunderbolt 5.

✔ USB-C 2.1

USB-C 2.1 certification introduces:

  • 40 Gbps USB cables
  • 80 Gbps USB Extended Range cables
  • Up to 240W Power Delivery

Power Delivery (PD 240W)

Supports:

  • Gaming laptops
  • High-end monitors
  • Workstations
  • Docking stations

✔ DisplayPort Alt Mode 2.1

Allows video output through USB-C.

Supported:

  • 4K 240Hz
  • 8K 60Hz
  • HDR10+
  • DSC compression

Required for:

  • USB-C monitors
  • Dex/ReadyFor desktop modes
  • Docking stations

✔ Thunderbolt 5

Thunderbolt 5 is the fastest cable interface ever released.

Features:

  • 80 Gbps standard bandwidth
  • 120 Gbps burst bandwidth
  • 8K display support
  • Dual 4K 240Hz support
  • 240W PD charging
  • PCIe 4.0 tunneling for eGPU setups

✔ Comparison Table

| Feature | USB-C 2.1 | DP Alt Mode 2.1 | Thunderbolt 5 | |--------|------------|------------------|----------------| | Bandwidth | 40–80 Gbps | — | 80–120 Gbps | | Max Resolution | Depends on DP | 8K60 | 8K60 / 4K240×2 | | Power Delivery | 240W | — | 240W | | Data Performance | High | Only video | Extremely high | | eGPU Support | No | No | Yes, best option |

✔ Which Technology Do You Need?

4K 144Hz / 240Hz monitor

→ USB-C DP Alt Mode 2.1 or Thunderbolt 5

8K monitor

→ Thunderbolt 5

Laptop charging

→ USB-C PD 3.1 (up to 240W)

External GPU

→ Thunderbolt 5 (ideal)
→ Thunderbolt 4 works but slower

Docking stations

→ USB-C 2.1 or Thunderbolt 5

✔ Why Cable Selection Matters

A USB-C cable must specify:

  • Power rating (60W / 100W / 240W)
  • Data rating (10G / 20G / 40G / 80G)
  • DP Alt Mode support
  • Thunderbolt certification

Wrong cable =
slow charging, no display output, reduced speed.

✔ The Future of USB-C & TB5

  • HDMI will become obsolete on laptops
  • All monitors will support USB-C/TB5
  • Single-cable “power + video + data” setups will dominate
  • Thunderbolt 5 will push external graphics to new limits

✔ Conclusion

USB-C 2.1 provides higher bandwidth and power delivery, DisplayPort Alt Mode enables high-resolution video, and Thunderbolt 5 delivers unmatched performance for professional and gaming environments.

Understanding these technologies ensures a future-proof setup.