Do you need DisplayPort 2.1 for 4K 240Hz? Bandwidth and cable guide

4K at 240 Hz with 10-bit 4:4:4 HDR needs 66.9 Gbps, which is 87% of DisplayPort 2.1 UHBR 20's 77.37 Gbps effective data rate. It fits natively, without Display Stream Compression, which is the selling point of DP 2.1 relative to DP 1.4 for high-end monitors.

Required bandwidth

66.9 Gbps

Uncompressed

With DSC

17.8 Gbps

Visually lossless 3:1

Mode

3840×2160 @ 240 Hz

10-bit 4:4:4

Interface Bandwidth Analysis

See how much uncompressed and compressed bandwidth this resolution and refresh rate mode demands, compared to the native limits of common video cables.

Uncompressed Signal66.9 Gbps

With Display Stream Compression (DSC)17.8 Gbps

DSC uses visually lossless 3-to-1 compression, shrinking the required bandwidth so it fits through older cables.

Cable Limits Reference

HDMI 2.0

14.4 Gbps

✗ Not supported

DP 1.4

25.9 Gbps

⚠ DSC required

HDMI 2.1

42.6 Gbps

⚠ DSC required

DP 2.1 (UHBR 20)

77.4 Gbps

✓ Native support

Display Mode: 3840 × 2160 @ 240 Hz

Color depth: 10-bit 4:4:4

Resolution

Refresh Rate: 240 Hz

Color Depth

Chroma

Required Bandwidth

Uncompressed

66.89 Gbps

With DSC (Display Stream Compression)

17.84 Gbps

Interface Compatibility

HDMI 1.4

✗ Incompatible

HDMI 2.0

✗ Incompatible

HDMI 2.1 (48G)

DSC Required

HDMI 2.2 (96G)

✓ Native

DisplayPort 1.2

✗ Incompatible

DisplayPort 1.4

DSC Required

DisplayPort 2.1 (UHBR 10)

DSC Required

DisplayPort 2.1 (UHBR 13.5)

DSC Required

DisplayPort 2.1 (UHBR 20)

✓ Native

How this is calculated

UHBR 10 (38.69 Gbps) and UHBR 13.5 (52.22 Gbps) can't reach this mode uncompressed and fall back to DSC. UHBR 20 is the tier you actually need for 4K 240 Hz HDR without any compression. Its per-cable physical reach is shorter than UHBR 13.5, which is why only certified-40G DisplayPort 2.1 cables (usually under 1 m) can sustain this bandwidth. This is the highest-fidelity desktop gaming mode available outside of HDMI 2.2 (96G) territory.

Verdict

66.9 Gbps demands DP 2.1 UHBR 20. It's the interface's reason to exist: future-proofing against the 4K 240 Hz and 1440p 480 Hz monitors that DP 1.4 + DSC can't fully serve at native quality.