- Connecting
- Need
- Answer
One cable for video, charging and USB
Get this
The USB-C or Thunderbolt cable that came with the monitor, or a Thunderbolt 4 cable (1 m, 100 W)
Look for
- Monitor: USB-C input with Power Delivery (65–100 W) and DisplayPort Alt Mode
- Cable: 100 W (5 A) and 10Gbps or faster; Thunderbolt 4 covers both
Avoid
- 240 W charging cables that are USB 2.0 only (no video)
- Cables over 1 m for 4K 60 plus USB 3 unless they are active Thunderbolt
The numbers: 4K 60 Hz 8-bit
| Link | Needs | Has | Result |
|---|---|---|---|
| USB-C DP 1.4 ×2 | 12.54 Gbps | 12.96 Gbps | Fits |
| USB-C DP 1.2 ×2 | 12.54 Gbps | 8.64 Gbps | Too much |
| Thunderbolt 4 | 12.54 Gbps | 25.92 Gbps | Fits |
How the numbers are worked out
Reduced-blanking timing (VESA CVT-R2)
3840×2160 active → 3920 × 2222 total pixels per frame
3920 × 2222 × 60 Hz = 522.61 MHz pixel clock
522.61 MHz × 24.0 bits per pixel = 12.54 Gbps
8-bit colour, full RGB/4:4:4: 3 × 8 = 24.0 bits per pixel.
"Has" is the link's usable rate after line coding. DSC is modelled as up to 3:1 compression. Full method.
Standards behind this answer
2014
DisplayPort over USB-C (Alt Mode)
How most USB-C ports send video. The USB-C pairs are handed over to DisplayPort.
- data: USB 2.0 or USB 3 alongside
- video: DP 1.4 (or 2.1) over USB-C
- power: USB PD at the same time
USB Power Delivery (60 W, 100 W, 240 W)
The charger and device agree a voltage; the cable decides whether 3 A or 5 A is safe.
- power: 60 W / 100 W / 240 W
Thunderbolt 4
The same 40 Gbps as Thunderbolt 3, with the minimums raised so every port behaves the same.
- data: 40 Gbps (PCIe 32 Gbps)
- video: two 4K 60 Hz or one 8K
- power: up to 100 W (USB PD)