When I plug in an external monitor to my MBP 16 (2019, Intel) it supports only up to 1080p but the same cable and monitor show 4k 30 FPS limit of the cable when plugged into my new Macbook Air M1. I can't find a solution to this. My 16 inch supports up to 2 4k displays (base model 16 inch). How to get it running at 4K 30 or 1440 p .The monitor I am using is Samsung M7 4K model.
MacBook Pro with Touch Bar
Do you have a link to the specs of that display? all I can find shows only a display with USB-C and nothing else.
Otherwise, it is the DISPLAY which tells the MAC about its capabilities. But
system preferences > displays ...
... shows only the "User Interface Looks like" resolution in most cases. You need to look instead at:
menu > about this Mac > (system report) > graphics & displays ...
The actual resolution will be shown first.
Then the "UI looks like" resolution will be shown below. This is what ONLY the textual elements would seem to be, except they have actually been drawn at a higher pixel-doubled resolution to be more legible.
Here are the specs as found on samsung's website Scroll to the bottom of the webpage to find them.
https://www.samsung.com/nz/monitors/flat/smart-m7-32-inch-uhd-4k-ls32am700uexxy/
The display works perfectly with my m1 MacBook Air but doesn't work properly with MBP 16 2019 and is capped at 1080p 30FPS while it works perfectly fine will full performance on M1 Air with the same HDMI adapter .
DisplayPort Dual-Mode (DP++), also called Dual-Mode DisplayPort, is a standard which allows DisplayPort sources to use simple passive adapters to connect to HDMI or DVI displays.
[...]
Devices which implement dual-mode will detect that a DVI or HDMI adapter is attached, and send DVI/HDMI TMDS signals instead of DisplayPort signals. The original DisplayPort Dual-Mode standard (version 1.0), used in DisplayPort 1.1 devices, only supported TMDS clock speeds of up to 165 MHz (4.95 Gbit/s bandwidth). This is equivalent to HDMI 1.2, and is sufficient for up to 1920 × 1200 at 60 Hz.
In 2013, VESA released the Dual-Mode 1.1 standard, which added support for up to a 300 MHz TMDS clock (9.00 Gbit/s bandwidth), and is used in newer DisplayPort 1.2 devices. This is slightly less than the 340 MHz maximum of HDMI 1.4, and is sufficient for up to 1920 × 1080 at 120 Hz, 2560 × 1440 at 60 Hz, or 3840 × 2160 at 30 Hz.
from wikipedia article:
https://en.wikipedia.org/wiki/DisplayPort#1.2
so on your "older" 2019 model Mac, lack of fancy new displayPort features limits its ability to support borderline HDMI features such as HDMI 4K at 30Hz. Since it cannot produce ONE signal that can drive the entire display, the lower resolution offered is intended to drive one half of the display. You are expected to connect an additional HDMI cable for the second half, and turn on the Picture-By-Picture feature in the display to put the two halves back together. The display has two HDMI inputs for exactly this scenario.
Your Newer M1 Mac has a more advanced DisplayPort, which supports more advanced HDMI capabilities when used with an adapter, and can support 4K at 30Hz directly on one cable, so that is offered as an option.
For the M1 your setup is:
1 HDMI connection
1 USB-C to DisplayPort
for the MBP 16 (2019, Intel)
1 USB-C to DisplayPort
I am using the same type c to HDMI adaptor in both cases but the 16 inch intel doesn't show up to 4k 30 even though it supports while the m1 air does .
External monitor support 4k UHD Macbook Pro 16 2019
