Glossary
Thunderbolt 4
Intel's high-bandwidth interconnect over USB-C. Provides 40 Gbps bidirectional, 100 W power delivery, daisy-chained dual 4K display support, and PCIe 3.0 ×4 tunneling. Standard on premium laptops.
Thunderbolt 4 keeps the 40 Gbps ceiling of TB3 but tightens minimum requirements: every TB4 port must support 100 W PD, dual 4K displays, and PCIe ×4 storage.
Real-world uses
- External GPU. PCIe 3.0 ×4 (about 32 Gbps after overhead) bottlenecks a high-end card, but a midrange eGPU + a thin laptop is now a viable workstation.
- Dock + monitor + power on a single cable. The flagship use case for hybrid work.
- NVMe enclosures. Sustained 3,000 MB/s — close to internal Gen 3 NVMe.
Versus USB4
USB4 borrows the TB protocol but only mandates 20 Gbps; TB4 mandates the full 40. A USB4 port may or may not match TB4 capabilities — the spec lets it ship at lower tiers.
Versus Thunderbolt 5
TB5 (2024+) doubles bandwidth to 80 Gbps symmetric (and 120 Gbps asymmetric for displays). Adoption is gated by chipsets — most laptops will not see it until 2025–2026 mainstream parts.
Where this matters
Categories that use thunderbolt 4
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