Key Differences Between Thunderbolt 5 (TB5) and Thunderbolt 4 (TB4)

Key Differences Between Thunderbolt 5 (TB5) and Thunderbolt 4 (TB4)

1. Bandwidth and Data Transfer Performance

• Thunderbolt 5: Provides a baseline bidirectional bandwidth of 80Gbps. With Bandwidth Boost technology, the downstream bandwidth can be increased to 120Gbps (while upstream is compressed to 40Gbps). This design is particularly beneficial for high-resolution video output, such as supporting a single 8K 120Hz display or multiple 4K 144Hz displays.

• Thunderbolt 4: Offers a fixed bidirectional bandwidth of 40Gbps, supporting dual 4K 60Hz displays, but has limitations for higher refresh rates or multi-display setups.

2. Power Delivery

• Thunderbolt 5: Supports up to 240W PD 3.1 charging, sufficient to directly power high-performance gaming laptops. It also provides 15W reverse power delivery.

• Thunderbolt 4: Limited to a maximum of 100W, with no clear enhancement in reverse power delivery.

3. Video Output Capabilities

• Thunderbolt 5: Capable of driving three 4K 144Hz displays simultaneously or a single 8K 120Hz display, with dynamic bandwidth allocation optimizing video data transmission.

• Thunderbolt 4: Supports only dual 4K 60Hz displays or a single 8K display (with compressed refresh rates).

4. Compatibility and Signaling Technology

• Thunderbolt 5: Uses PAM-3 signaling technology and is compatible with the USB4 V2 standard, simplifying design complexity and improving device interoperability.

• Thunderbolt 4: Retains the Thunderbolt 3 physical layer, compatible with USB4 but not optimized for next-generation standards.

5. Extended Application Scenarios

• Thunderbolt 5: With stronger bandwidth and power delivery, it is well-suited for external AI accelerators, high-performance eGPUs, and professional workloads requiring ultra-fast storage transfers.

• Thunderbolt 4: Primarily designed for general expansion needs, such as connecting peripherals and handling moderate display output requirements.

6. Cost and Market Adoption

• Thunderbolt 5: Relies on independent controller chips, leading to higher costs. As of early 2025, market adoption remains limited, with fewer mass-produced devices.

• Thunderbolt 4: Mature and widely adopted, already integrated into Intel Core processor platforms, with more affordable implementation.

In summary, Thunderbolt 5 significantly outperforms Thunderbolt 4 in terms of bandwidth, power delivery, and video output. However, in the short term, adoption may be limited by cost and ecosystem readiness. Thunderbolt 4, meanwhile, remains more practical for mainstream users with moderate performance needs.