what is the maximum 8k refresh rate supported by the hdmi™ 2.1b on the msi rtx 5090 with dsc?

The HDMI™ 2.1b port on the MSI RTX 5090 with DSC supports a maximum of 8K at 120 Hz.

Quick Scoop

• MSI’s own RTX 5090 product pages list the HDMI 2.1b output as supporting:
  • 4K up to 480 Hz with DSC.

* 8K up to 120 Hz with DSC (HDR and VRR supported).

• Industry coverage of RTX 5090 display support notes higher 8K refresh (up to 165 Hz) via DisplayPort 2.1b + DSC , not HDMI; HDMI is specified up to 8K 120 Hz with DSC.

So, for your exact question — “what is the maximum 8K refresh rate supported by the HDMI™ 2.1b on the MSI RTX 5090 with DSC?” — the answer is:

8K 120 Hz (with DSC over HDMI 2.1b).

At the moment, anything above 8K 120 Hz on this card is only documented as possible over DisplayPort 2.1b with DSC, not over HDMI.

TL;DR: HDMI 2.1b on the MSI RTX 5090 tops out at 8K 120 Hz with DSC , even though DisplayPort 2.1b on the same card can go higher at 8K with DSC.

Information gathered from public forums or data available on the internet and portrayed here.