Mac Pro 2019 MacPro2019 macOS Display Does Not Show 5120x2160 or res, But Can Work

... i/m/we're posting more info related to above problems ...

MORE INFO / DESCRIPTION :

LG UltraWide Monitor:

LG 34BK95U - W

( LG 34BK95U - WY )

Monitor's manual is showing:

HDMI : 3440 x 1440.

USB-C / Thunderbolt 3⚡/ DP : 5120 x 2160.

This LG monitor is connected to Mac Pro 2019 Tower's top-side one of the Thunderbolt3⚡/ USB-C port.

Thunderbolt 3⚡ cable is the original, which came with this LG Monitor, is used for that.

Other Thunderbolt 3⚡ port (in top-side of tower MacPro2019) is (purposefully kept) empty.

PCIe slot-8 is an I/O card, it's output is in the back side of Mac Pro,

this ( I/O card ) has two Thunderbolt 3⚡/ USB-C ports,

but i/we did not test Monitor from that/those, as this is a lesser bandwidth or narrow bit lane based PCIe card which has all the other Thunderbolt 3 and USB devices.

LG Monitor is showing Alert message :

..Use recommended display settings 5120x2160 res (resolution)..

this Alert message is appearing every-time when MacPro wakes up from sleep/hibernation.

So far what i/we observed:

when Mac Pro 2019 goes into deep sleep or deep hibernation ( i/we think, when we leave it for 6 to 8 hours or more), then, after wakeup it can goto 5120x2160 res, ( but the "Displays" info incorrectly shows its still in 3440x1440 res !! ).

But once i/we start to use,

and leave it for a while,

its going into normal 1st stage sleep mode, and coming back, etc, etc

( and it can still remain in 5120x2160 res 🙂😀 ).

But after few hours (or when it can goto 2nd or next sleep stage mode) ,

then after wakeup, it again switches back to lower res 3440x1440 !! 🙁☹ :(

( and "Displays" info incorrectly shows 5120x2160 res !! )

if sleep mode is changing graphics related I/O related mem-loc or graphic high-res paging mode, etc , then those need to be addressed + handled when Mac Pro wakes-up.

Just noticed this: the macOS 12.6 update can immediately switch-to & use 5120x2160 res during update/installation 🙂😀 :) ,

but when update/installer reaches to "10 minutes remain...",

then after few times of screen flickering or screen going dark ,

screen resolution switched into 3440x1440 lower-res ! :( 🙁☹

( res = resolution )

in macOS v12.6 , Display res is still behaving unexpectedly:

after few times of

MacPro screen-saver activates (after 10 minutes),

then 2 minutes later, "Energy Saver" turns off the Display or puts it into sleep mode.

When i/we stat using it again, we move keyboard's arrow buttons to bring it out of sleep mode,

macOS user login screen appears.

but after few times of going into sleep & wake-up, MacPro's macOS again switches the Display resolution into 3440x1440 lower resolution 🙁☹ :( , instead of remaining in 5120x2160 !!