MacBook Pro 16" with LG Ultrafine 4k 24" 2019 model

[lambrosn]

hi, I recently purchase a MacBook Pro 16 with the amd radeon pro 550m with 8gb. Also I purchased the LG UltraFine 4k from apple store.



my setup is MacBook pro 16" with one monitor lg UltraFine 4k 2019 model connected with a single usb-c cable either from apple store the proper one , or from lg which I have in the package.



fully updated both to latest versions.



please have a look first of my system report:







I see in the resolution 8K!! how is this possible or I am missing something? I have one monitor.



I have a huge problem though.. when I am playing 4k videos through chrome browser in full screen then the video is sloppy and losing frames. same happens with all 4k videos. In parallel if I play same videos at my tv then all are smooth. so tv produce better 4k play than MacBook Pro 16 and lg UltraFine?? I can't believe this.



my internet connection is fast 120 mbps the cable is the proper one I am using .so where is the problem???



the videos when are in native small window in 4k they play ok in chrome, when I maximise them then problem start.



safari can not play 4k videos so the test has been done to chrome and Firefox with same results!!!!



please any idea?

 

[joevt]

macOS does not tell you what the output signal is.

What you are seeing is the frame buffer size which is 8K. "UI looks like 3840 x 2160" means it's a HiDPI mode (Retina mode) where text and objects are drawn twice as tall and wide as for a non-Retina mode. The GPU scales the 8K frame buffer to the output signal resolution/timing 4K 60Hz.

Try using a 4K low resolution mode instead of the 4K retina mode.
System Preferences -> Displays -> hold option key and click Scaled -> select "Show low resolution modes" -> select "3840 x 2160 (low resolution)".

You can use SwitchResX to see all the timings. To see what the output signal is for a timing, double click the timing in the Current Resolutions tab for the display in SwitchResX. For the resolution you are showing in your screen shot, the timing will probably be "3840 x 2160 , 60Hz (NTSC)", HiDPI, Pixel Clock: 533 MHz, Active: 3840 x 2160, Scale to: 7680 x 4320. All the numbers except "Scale to" describe the output signal (it's missing pixel format though which may differ from the Frame Buffer Depth pixel format).

The modes that you should usually use are the HiDPI modes "1920 x 1080" or "2560 x 1440" or "3008 x 1692" which use frame buffer sizes like 3840 x 2160, 5120 x 2880, or 6016 x 3384. Actually, "1920 x 1080" might be good for playing 4K since the frame buffer size will be 4K.

 

[lambrosn]

macOS does not tell you what the output signal is.

What you are seeing is the frame buffer size which is 8K. "UI looks like 3840 x 2160" means it's a HiDPI mode (Retina mode) where text and objects are drawn twice as tall and wide as for a non-Retina mode. The GPU scales the 8K frame buffer to the output signal resolution/timing 4K 60Hz.

Try using a 4K low resolution mode instead of the 4K retina mode.
System Preferences -> Displays -> hold option key and click Scaled -> select "Show low resolution modes" -> select "3840 x 2160 (low resolution)".

You can use SwitchResX to see all the timings. To see what the output signal is for a timing, double click the timing in the Current Resolutions tab for the display in SwitchResX. For the resolution you are showing in your screen shot, the timing will probably be "3840 x 2160 , 60Hz (NTSC)", HiDPI, Pixel Clock: 533 MHz, Active: 3840 x 2160, Scale to: 7680 x 4320. All the numbers except "Scale to" describe the output signal (it's missing pixel format though which may differ from the Frame Buffer Depth pixel format).

The modes that you should usually use are the HiDPI modes "1920 x 1080" or "2560 x 1440" or "3008 x 1692" which use frame buffer sizes like 3840 x 2160, 5120 x 2880, or 6016 x 3384. Actually, "1920 x 1080" might be good for playing 4K since the frame buffer size will be 4K.

thank you very much.

my resolutions are (see attached)

so for me in order to view my drone 4k 60 frames video, i am editing in final cut pro or youtube 4k videos without losing frame is to choose from the screenshot the 3008x1692?

for the switch resx app i don't have it but I will check it.

 

[lambrosn]

problem solved ))))))). i used switchresx and i choose the 3840 x 2160 (not scaled) so now i have in the system report the attached .

the resolution is not HIDPI , do i lose something in the quality of the videos.

then i played 4k video from youtube and no stuck no-lose frame all smooth



thank you man!!!

 

[joevt]

problem solved ))))))). i used switchresx and i choose the 3840 x 2160 (not scaled) so now i have in the system report the attached .

the resolution is not HIDPI , do i lose something in the quality of the videos.

then i played 4k video from youtube and no stuck no-lose frame all smooth

The video should behave the same whether you choose 3840 x 2160 or 1920 x 1080 HiDPI (both have the same frame buffer size). Text will appear smoother in HiDPI mode but that doesn't matter if you're playing video at full screen.

Higher resolution modes like 6016 x 3384 or 3008 x 1692 HiDPI have more pixels and require additional scaling for full screen mode but maybe you can play them at 100% size (no scaling - not full screen) to get better performance? Then you can try the macOS Zoom mode (in Accessibility preferences panel) to fill the screen (because Zoom mode may have a more efficient scaling method). The best way to use Zoom mode is to move the window until the video is at the bottom of the screen, move the cursor to the bottom of the screen in the horizontal centre of the video, then zoom in until the video fills the screen.

 

[lambrosn]

The video should behave the same whether you choose 3840 x 2160 or 1920 x 1080 HiDPI (both have the same frame buffer size). Text will appear smoother in HiDPI mode but that doesn't matter if you're playing video at full screen.

Higher resolution modes like 6016 x 3384 or 3008 x 1692 HiDPI have more pixels and require additional scaling for full screen mode but maybe you can play them at 100% size (no scaling - not full screen) to get better performance? Then you can try the macOS Zoom mode (in Accessibility preferences panel) to fill the screen (because Zoom mode may have a more efficient scaling method). The best way to use Zoom mode is to move the window until the video is at the bottom of the screen, move the cursor to the bottom of the screen in the horizontal centre of the video, then zoom in until the video fills the screen.

thank you !