ROG Z690 Hero Thunderbolt 4 display output capped at 60Hz

[ringmaster555]

• Operating System: Windows 11 Pro x64
• BIOS Version: 2305
• Thunderbolt Driver Version: 1.41.1353.0
• Monitor: LG OLED Flex with Deep Color Mode enabled on HDMI input
• Cable: Stouchi 8K HDMI 2.1 Cable 6ft 48Gbps
• Adapter: Cable Matters 48Gbps USB C to HDMI 2.1 Adapter with VMM6100 Chipset

Additional notes:

• The cable, adapter, and display are confirmed working at 120Hz on other Thunderbolt 4 equipped PCs.
• List all modes in Windows Display adapter properties and Intel Graphics Command Center are also capped at 60Hz
• PCIe Passthrough enabled (I have an RTX 4080)

[ringmaster555 · Accepted solution]

Found a fix! Updating the Cable Matters adapter firmware to version 6.05.120 results in 120Hz output. In case anyone else has the same issue, here's a link to update the firmware: https://kb.cablematters.com/index.php?EntryID=153&View=entry