In this guide
Thunderbolt 4 supports 40 Gbps bidirectional data, dual 4K or single 8K displays, PCIe at minimum 32 Gbps, up to 100W charging, daisy-chaining up to 6 devices, docks, external GPUs, and all USB-C peripherals — using a certified Thunderbolt 4 cable over a standard USB-C port.
- You use a certified Thunderbolt 4 cable (up to 2m for full 40 Gbps)
- Host and device both support Thunderbolt 4 or USB4
- Intel VT-d DMA protection is enabled on the host
- Dock or adapter used for multi-monitor or PCIe expansion
- Non-certified cables reduce speed to USB4/32 Gbps or less
- Older Thunderbolt (pre-3) devices need adapters and may not hit full PCIe 32 Gbps
- Bandwidth sharing reduces throughput after video overhead (~22 Gbps peak data)
- Host lacks sufficient power delivery for 100W charging with multi-8K displays
Thunderbolt 4 at a Glance
Thunderbolt 4 uses the USB-C connector and delivers 40 Gbps in both directions simultaneously. That single port can carry data, video, power, and PCIe signals at the same time. According to the Intel Thunderbolt 4 technology brief, every certified port must meet a strict minimum spec — unlike USB4, which has tiered performance levels.
Display Support
Thunderbolt 4 carries DisplayPort 1.4 or 2.0 signals, giving you flexible display options from a single port. If you need to connect a monitor via HDMI, check out how USB-C connects to HDMI for adapter guidance.
- Dual 4K monitors at 60 Hz
- Single 8K monitor at 60 Hz
- Up to three 10K displays via a Thunderbolt dock
What Can You Connect?
| Setup | Works? | Need | Note |
|---|---|---|---|
| Thunderbolt 4 dock | Yes | TB4 cable | Daisy-chain up to 6 devices |
| Dual 4K monitors | Yes | TB4 dock or MST hub | DisplayPort 1.4/2.0 |
| External GPU | Yes | TB4 cable + eGPU enclosure | PCIe min 32 Gbps |
| High-speed SSD | Yes | TB4 cable | Up to ~3 GB/s real-world |
| USB-A/HDMI peripherals | Yes | TB4 dock or adapter | Full backward compatibility |
| Thunderbolt 3 device | Yes | TB3 cable | Runs at TB3 speeds (40 Gbps) |
| Thunderbolt 1/2 device | Yes* | TB3 adapter + TB1/2 cable | May not reach PCIe 32 Gbps |
| Non-certified USB-C cable | Partial | — | Capped at USB4/32 Gbps or less |
Power Delivery
Thunderbolt 4 ports can charge connected devices at up to 100W. When running demanding peripherals simultaneously, total available power is shared across the bus, so very high display loads may reduce charging headroom.
Bandwidth Sharing to Know About
The 40 Gbps total is shared across everything running at once. Driving a 4K display consumes a portion of that bandwidth, leaving roughly 22 Gbps peak for data transfers. If USB-C video and file transfers run together, expect real-world data speeds closer to that lower ceiling rather than the full 40 Gbps figure.
Bottom line: Thunderbolt 4 is the most capable single-cable connection available today — covering displays, high-speed storage, PCIe expansion, and charging in one certified port. Use a certified Thunderbolt 4 cable, confirm your host and device both carry the TB4 logo, and you will get the full 40 Gbps experience with no guesswork.