Ultrawide resolution missing on new macOS 15.6 update

that G95SC appears to be a 5120 wide by 1440 tall display, similar to a 5K display with the bottom half missing.

it supports 10 bits/color HDR=ON (which requires about 25% more bandwidth that 8 bits/color)

Interfaces include:

HDMI 2.1

DisplayPort 1.4

USB-C, mainly for peripherals

Your MacBook Pro 2019 does not have a direct HDMI Port, so HDMI can not be used for one-cable connection.

Standard timings for a 5K wide display, (or extended timings for a short 5K display) suggest that either:

Certified USB-C cables marked with SuperSpeed PLUS logo or USB-10 or USB-20 logos would work, but the length is limited to ONE meter or shorter.

USB-C to DisplayPort adapter/cable must also meet that length limit -- no longer than ONE meter of USB cable before the adapter, and no more than ONE meter of DisplayPort cable after the adapter.

Cables that are too long will cause transmit errors, and recent MacOS will either reduce the resolutions available or shut off the display.

ahiguera23 wrote:

Did Apple make changes to how they extend displays? looks like now it's mirroring instead of extending even when you choose the extension option. This is missing the appropriate resolution for a 49" ultra wide Samsung Odyssey. Everything looks very stretched out even on the highest resolution they have available, (3840 x 2160) . I can't exactly recall the resolution that worked for this but it may have been 3840 x 2440. Anyone know how to fix this or if we have to wait on another update from apple?

MacBook Pro 16″, macOS 15.6

Verify your software is up to date…

The current stable release of Sequoia including bug fixes, security updates is macOS 15.6.1

Keep your Mac up to date - Apple Support

Keep your Mac up to date - Apple Support

No direct help, but I still have the 5120 x 2160 ultra wide option on my Macs running 15.6.1.

Clearly the monitor can support 5120 x 1440, your Mac (any 16" MBP that can run Sequoia) should drive it at full resolution.

Report issues to Apple here:

Feedback - macOS - Apple

I can see from your screenshot that your external is set as the main display - AND your internal must surely be set to "Mirror Odissey ...".

I could see how mirroring would limit the available resolutions.

Click on the internal and change from mirroring to extending. Does that change the options for the external?

<< My Mac is a 2023, not a 2019. >.

Then you should connect to that display using a certified ULTRA HDMI cable for highest possible data rates:

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"PREMIUM High Speed HDMI cable" or that + "with Ethernet" (up to 4K at 30Hz) --OR--

“ULTRA High Speed HDMI cable" or that + "48G" (supports higher resolutions and backward-compatible)

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

HDMI was invented for HD TV sets. it works great at its original resolution of 720i or 720p. At higher resolutions, it quickly develops issues that are complex to solve, and the cables and adapters required to solve are NOT intuitive.

Depends which MacOS enabled device you have.

Did you try turning ON "Show all resolutions"?

If it still does not work, I'd try installing and running "BetterDisplay":

https://github.com/waydabber/BetterDisplay