Do you need DisplayPort 2.1 for 4K 240Hz? Bandwidth and cable guide
68.6 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.
4K at 240 Hz with 10-bit 4:4:4 HDR needs 68.6 Gbps, which is 89% 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.
By TechCompare · Updated
Interface Bandwidth Analysis
See how much uncompressed and compressed bandwidth this resolution and refresh rate mode demands, compared to HDMI and DisplayPort connections.
DSC uses visually lossless 3-to-1 compression, shrinking the required bandwidth so it fits through older cables.
Other connections
Assumes display traffic only and four DisplayPort lanes for USB-C. USB4 and Thunderbolt figures are for one DisplayPort stream.
Calculator
Display Bandwidth Calculator
Required Bandwidth
Uncompressed
68.56 Gbps
With DSC (Display Stream Compression)
18.28 Gbps
Interface Compatibility
HDMI
DisplayPort
Other connections
Assumes one display with no USB or PCIe data sharing. USB-C uses all four DisplayPort lanes. USB4 and Thunderbolt use the DisplayPort profile listed. The 120 Gbps modes add bandwidth for multiple streams, while one DP 2.1 UHBR 20 stream stays at 77.37 Gbps. Compare checks each display separately.
USB-C
Thunderbolt
USB4
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
4K at 240 Hz with 10-bit 4:4:4 HDR needs 68.6 Gbps, 89% of DisplayPort 2.1 UHBR 20's 77.37 Gbps effective data rate, so it fits natively without DSC. The lower UHBR tiers can't reach this mode uncompressed: UHBR 13.5 (52.22 Gbps) and UHBR 10 (38.69 Gbps) both fall back to DSC. UHBR 20 is the tier that actually delivers 4K 240 Hz HDR natively, and its physical reach is shorter than UHBR 13.5, which is why certified 40G DP 2.1 cables reliably sustain this mode only under about 1 meter passive or 3-5 meters with an active optical cable. That's the price of native uncompressed 4K 240 Hz, and it's why DP 2.1 UHBR 20 exists.
More DisplayPort 2.1 scenarios
Related guides
Frequently asked questions
Does 4K 240Hz require a DisplayPort 2.1 graphics card?
Which GPUs support DisplayPort 2.1 for 4K 240 Hz?
How far can a DisplayPort 2.1 UHBR 20 cable reach for 4K 240 Hz?
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