External Monitor 4K Resolution Capped at 30Hz Only for EliteBook 660 G11 via Thunderbolt Connection

[Epidural3269]

Monitor

• LG 43" MyView Smart Monitor (43SQ700S) with USB Type-C and 4K UHD Display

Windows Device (4K 3840x2160 resolution capped at 30Hz)

• System Model: HP EliteBook 660 16 inch G11 Notebook PC

• System SKU: 9Y2V8AV (This is a model sold to SMBs in Japan, offered to me by the company I am working for)

• Processor: Intel(R) Core(TM) Ultra 7 165U 1.70 GHz

• Display Adapter: Intel(R) Graphics

• Display Output Ports: 2x Thunderbolt 4 40 Gbps ports, 1x HDMI 2.1 port

• OS: Windows 11 24H2 (26100.1)

Mac Device (4K resolution works fine at 60Hz)

• Model: MacBook Air (M2, 2022 · Z15T002LTJ/A · Mac14,2)

• Display Output Ports: 2x Thunderbolt 4 Ports

• OS: macOS 15.1.1 (24B91)

Cables I tried

• USB Type-C cable that comes with LG Monitor. Specs unknown.

• Anker 515 USB-C to USB-C Cable (Thunderbolt 4 Compatible)

• Anker USB-C to USB-C Thunderbolt 4 100W Cable (2.3 ft)

Troubleshooting I tried

The 60Hz option is available while followed by a star. When selected the resolution will be set to FHD 1920x1080 @ 60Hz.

I contacted HP support, and they asked me to enable "High resolution mode when connected to a USB-C DP alt mode dock" in BIOS settings. I did so but the refresh rate is still capped to 30Hz.

HP support also told me to uninstall display adapter driver in Device Manager, and reinstall it by using the exe file downloadable from their support site. This also did not work.

I also tried to set color format to YCBCR_444 in Intel Graphics Command Center but nothing happened.

The issue above only exists when connecting the HP laptop to the monitor with a single USB Type-C/Thunderbolt cable. HDMI cable works fine for the HP laptop.

I just cannot figure out whether this is a limit of the monitor, the cables, or the Thunderbolt 4 ports on HP laptop.

[Epidural3269]

HP Japan Support contacted me again saying that peripherals are not guaranteed to work properly, which is a total non-sense to me.

Since it is a Thunderbolt 4 port and should have enough bandwidth to work with 4K@60Hz .

If HP cannot assure the precise spec that a Thunderbolt 4 port should provide, please consider remove the confusing Thunderbolt icon printing on the laptop body, alongside the spec description on your website.

[Epidural3269]

So no one in HP ever cares about this issue? Please do not let me define the Thunderbolt 4 ports on EliteBook products are a total scam.