Monitors – resolution, refresh rate and the right interface
How resolution, refresh rate and interface bandwidth relate to each other. When HDMI 2.0 is enough, when you need DisplayPort 2.1 or HDMI 2.1, and what DSC does.
The short version
- Resolution × refresh rate × colour depth = the data rate that the graphics card, the cable and the monitor must all handle.
- HDMI 2.0 goes up to 18 Gb/s, HDMI 2.1 up to 48 Gb/s, HDMI 2.2 up to 96 Gb/s. DisplayPort 2.1 with UHBR20 up to 80 Gb/s.
- If something in the chain cannot handle the requested mode, the system will offer a lower refresh rate or resolution.
Three numbers that must line up
When a monitor offers, say, 2560 × 1440 at 165 Hz, it means the graphics card has to send 165 frames every second, each with almost 3.7 million pixels. Add to that the colour depth (8 or 10 bits per channel) and the transmission overhead. The resulting data rate must be handled by:
- the output on the graphics card or laptop,
- the cable,
- the monitor’s input.
The weakest link decides what you see.
Bandwidth according to the specifications
| Interface | Maximum bandwidth | Source |
|---|---|---|
| HDMI 2.0 | 18 Gb/s | HDMI Forum, 2013 |
| HDMI 2.1 (Ultra High Speed HDMI Cable) | 48 Gb/s | HDMI LA |
| HDMI 2.2 (Ultra96 HDMI Cable) | 96 Gb/s | HDMI Forum, 2025 |
| DisplayPort 1.3 / 1.4 | 32.4 Gb/s (4 × 8.1 Gb/s) | VESA |
| DisplayPort 2.1 UHBR10 (DP40 cable) | 40 Gb/s | VESA |
| DisplayPort 2.1 UHBR20 (DP80 cable) | 80 Gb/s | VESA |
These are raw link rates. Part of them goes on encoding, so less is left for the picture. When a monitor uses the full bandwidth, it often also relies on DSC compression – for DisplayPort 1.4, VESA quotes a compression ratio of up to 3:1, which its member companies judged visually lossless in testing.
What it looks like in practice: for its RTX 50 cards, NVIDIA lists up to 4K at 480 Hz or 8K at 165 Hz over DisplayPort 2.1b with DSC.
The cable is part of the chain
HDMI 2.1 (48 Gb/s) needs a certified “Ultra High Speed HDMI” cable; HDMI 2.2 needs an “Ultra96” cable. HDMI LA states that certified cables carry a certification label with a QR code on the packaging. For DisplayPort, VESA certifies DP40 (up to UHBR10) and DP80 (up to UHBR20) cables.
USB-C as a monitor output
Many laptops have no separate DisplayPort, and send video over USB-C in DisplayPort Alt Mode, or via USB4 or Thunderbolt. Not every USB-C port can do this, though – makers usually mark it with a DisplayPort or Thunderbolt icon next to the port, or state it in the specification.
How to choose
Decide based on your work, not on the highest number. For text and spreadsheets, a higher resolution helps (sharper text); for games and fast motion, a higher refresh rate; for photos, colour gamut coverage and calibration. Compare the interfaces on one axis with the Interface speeds tool.
Before you finish
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Notes and sources
- HDMI Forum: HDMI Forum Releases Version 2.0 (up to 18 Gb/s)
- HDMI Licensing Administrator: Ultra96 and Ultra High Speed HDMI Cable (96 and 48 Gb/s)
- audioXpress (report on HDMI 2.2): HDMI Forum Releases HDMI Version 2.2
- VESA: VESA Publishes DisplayPort Standard Version 1.4
- VESA: VESA Releases DisplayPort 2.1 Specification (UHBR10/UHBR20, DP40/DP80 cables)
- NVIDIA: GeForce RTX 50 comparison – TGP, recommended PSU wattage, connectors
We opened every link above and compared the figures on 12 October 2026. The pages belong to their publishers and can change after that date.
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