HDMI 2.1 vs 2.0: Do You Really Need 48Gbps?

I built the CablePick finder because '4K' is no longer a specific enough term. To understand if you need an HDMI 2.1 cable, we have to look at Total Aggregate Bandwidth.

The Bandwidth Gap

HDMI 2.0 uses TMDS (Transition Minimized Differential Signaling) and is capped at 18Gbps. This is sufficient for 4K at 60Hz with 8-bit color.

HDMI 2.1 introduces FRL (Fixed Rate Link), which allows for up to 48Gbps. This jump is what enables 4K at 120Hz or 8K at 60Hz. If you are a PS5 or Xbox Series X user, or using a high-end PC GPU like the RTX 40-series, 18Gbps becomes a bottleneck, leading to black screens or downgraded chroma subsampling (4:2:0).

Comparison at a Glance

Feature	HDMI 2.0	HDMI 2.1
Max Bandwidth	18 Gbps	48 Gbps
Max Resolution	4K @ 60Hz	10K @ 120Hz
Signaling	TMDS	FRL
Dynamic HDR	No	Yes

My Recommendation

I suggest only upgrading to an 'Ultra High Speed' (2.1) cable if your display and source both support HDMI-VRR or 120Hz. For a standard office monitor or a 60Hz TV, an 'High Speed' (2.0) cable is technically identical in performance and often more flexible.

Technical References

• HDMI Forum: HDMI Specification 2.1b Public Release Summary.
• CTA-861-H: A DTV Profile for Uncompressed High-Speed Digital Interfaces.