Why doesn't Valve's Steam Machine support HDMI 2.1?

The Steam Machine hardware supports HDMI 2.1, but ongoing development of Linux drivers prevents full software implementation of the standard.

What workaround does Valve use for HDMI on Steam Machine?

Valve employs chroma sub-sampling to achieve higher frame rates like 4K at 120Hz over the limited bandwidth of HDMI 2.0 drivers.

Can the Steam Machine do 4K 120Hz?

Yes, the Steam Machine can achieve 4K at 120Hz using a technique called chroma sub-sampling, despite not fully supporting HDMI 2.1.

Home / Technology / Steam Machine Skips HDMI 2.1 Due to Linux Driver Woes

Steam Machine Skips HDMI 2.1 Due to Linux Driver Woes

5 Dec, 2025

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Summary

Steam Machine hardware supports HDMI 2.1, but software limitations prevent full implementation.
Linux drivers are the primary obstacle to achieving HDMI 2.1 functionality.
Valve uses workarounds like chroma sub-sampling to achieve higher frame rates on HDMI 2.0.

Valve's upcoming Steam Machine faces a hurdle with its video output, as the official specifications list HDMI 2.0 instead of the newer HDMI 2.1 standard. Despite the hardware's capability for HDMI 2.1, ongoing issues with Linux drivers, which are still under development, prevent its full implementation.

The HDMI Forum's restrictions on open-source implementations have significantly complicated matters for Valve. This necessitates testing the hardware on Windows and using workarounds like chroma sub-sampling in SteamOS. This technique allows for higher frame rates, like 4K at 120Hz, by compressing color information, though it may slightly impact video quality.

Furthermore, the lack of full HDMI 2.1 support limits adaptive sync capabilities, specifically preventing HDMI-VRR while only supporting AMD's FreeSync over HDMI. While these limitations may not be critical for most users, they highlight the challenges Valve encounters when developing Linux-based gaming hardware.