MacBook Pro M4: HP Dock limits Samsung G9 resolution

<< However, I have previously managed to run 2560 × 1440 at 180Hz through this dock. >>

2K display is less than half the bandwidth required to run your big 5K wide display. Resolution, bits/color, and refresh rate each multiply the number of bits/second that need to fly though those cables at very close to the physical ability to switch their digital logic.

The HP spec says it generally is not promised to support higher than 60 Hz, and does not support more than a 4K display at any refresh rate.

That dock does not appear to be a good match for your high-end display.

G9 is a family of displays. what model number is yours, exactly?

that Dock does not appear to support anything higher than 4K at 60, far short of what you seek for your G9 family display, typically capable of 5120 by 1440 (like 5K display with the bottom part missing).

Dock spec sheet here:

https://www8.hp.com/h20195/V2/GetPDF.aspx/4aa7-1989enw

that looks like nothing higher than 60 Hz is ever supported, and only one up to 4K at 60 Hz as its top resolution.

YES, the bottleneck is that Dock.

Is your Mac M2 or higher?

if so, its DIRECT HDMI port is the highest resolution available out of the Mac.

that Samsung LS49CG934SUXEN display is indeed a 5120 by 1440 display (like 5K display with the bottom part missing). with HDR 10 bits/color capable of refresh rates up to 240 Hz.

features include Picture-by-Picture, so it could support two-cable connection.

interfaces include on micro-HDMI and a HDMI to Micro HDMI cable is said to be included

also, full-size HDMI (support for resolutions above 4K require HDMI 2.1 and ULTRA certified cables.)

DisplayPort

Samsung pictures this display on their web site saying it can be used (with two cables) as if it were two 2560 by 1440 displays.

the Mac is ready, willing, and able to drive each half display (Left and Right) over separate cables, and use the Arrange pane to place them back together, side-by-side in the correct order. Users who have used this feature say that once set up. it works as one display without compromise.

Could the dock be the limiting factor here?

from what you describe it's pretty much the case.

if you need the dock for others things then if it was me then I would connect one thunderbolt cable to the monitor and another to the dock and let that be the resolution.