Ventura 13.4 gives no 120 hz option for external LG 4K OLED TV used for main monitor

Attached via HDMI cable (rated 8K, 48Gbps) 4 ft long between a 4k LG 48 inch OLED TV ( 2023 model OLED48C3AUS) 120 Hz refresh rate and brand new Mac Studio M2 Max running Ventura 13.4.


Under Displays there is no 120Hz refresh rate offered on the menu. Max refresh rate offered is 60 Hz. Why?


Went into the advance settings but that only offers mouse settings and Energy options. Weird place to put these options.


Note: I understand LG supplies the LED/OLED panels for the Mac monitors and Samsung and Sony TVs. So if the $1300 LG TV is recognized why not its 120 Hz refresh rate? Missing driver? Misrepresentation of refresh rate on Costco website and in-store display? No refresh rate advertised on the LG box the TV came in.


Help!

Mac Studio, macOS 13.4

Posted on Jul 19, 2023 5:18 PM

Reply

Similar questions

6 replies

Jul 20, 2023 5:48 PM in response to Jim Wainscott

Hi Jim Wainscott,


As long as the requirements are met, it should work for you. If you're only seeing the 60Hz option, it could be the cable itself not functioning properly, or it could be as you mentioned and an issue with the display itself not reporting the refresh rate correctly.


If possible, we'd recommend trying another cable to start, since that would be the simplest thing to try next.


Cheers.

Jul 24, 2023 1:33 PM in response to jmarse1

Problem solved.


I needed to plug the cable into to the back port (port 4 labeled HDMI 4k) The 3 side HDMI ports appear to all be eARC/ARC though only port 2 is labeled specifically such. I originally had cable plugged into side port HDMI 1. At 3840 x 2160 resolution the Mac Studio will occasionally lose communication with the LG unit but at 1920 X 1080 communication is stable. However the 120Hz option is available for both resolution settings as it should be.


Cable manufacturer is Rocketfish.

Certified Ultra High Speed label.

Is in-wall rated.

Length - 4ft,

Rated at 48Gbit, 4K at 120Hz, 8K at 60Hz, up to 10K, Dynamic HDR.

Price at Best Buy brick and mortar store - $40.

Perhaps subject to too much crosstalk between video channels at "4K" ( 3840 x 2160) resolution?

Better cables start at $100 up to $500 (most not seen in stock during today's visit to Best Buy, July 24).


Note:

Apple Store at Crabtree Mall, Raleigh NC, said to call LG.

Went then immediately to close by Best Buy to confirm or rule out the Rocketfish cable but found no qualified technical help there so I kept the cable.


Note: UPS courtesy of Teamsters Union may be going on strike July 31. Amazon depends on UPS. Plan your peripheral purchases accordingly.


Will keep the resolution at "2K" 120Hz due to eyesight issues and 4k communication issues with cable - for now anyway.


Jul 24, 2023 3:27 PM in response to Jim Wainscott

Your server apparently crashed during my edits to the above posting.

Here is the try again:


Problem solved.


 


I needed to plug the cable into to the back port (port 4

labeled HDMI 4k) The 3 side HDMI ports appear to all be eARC/ARC though only

port 2 is labeled specifically such. Or side port 1 may be defective. I

originally had cable plugged into side port HDMI 1. 

 


For the back port: At 3840 x 2160 resolution the Mac Studio

will occasionally lose communication with the LG unit but at 1920 X 1080

communication is stable. However the 120Hz option is available for both

resolution settings as it should be.

 


Cable manufacturer is Rocketfish.


Certified Ultra High Speed label.


Is in-wall rated. 


Length - 4ft,


Rated at 48Gbit, 4K at 120Hz, 8K at 60Hz, up to 10K, Dynamic

HDR.


Price at Best Buy brick and mortar store - $40.


Perhaps subject to too much crosstalk between video channels

at "4K" ( 3840 x 2160) resolution?


Better cables start at $100 up to $500 (most not seen in

stock during today's visit to Best Buy, July 24).


 


Note:


Apple Store at Crabtree Mall, Raleigh NC, said to call LG.


Went then immediately to close by Best Buy to confirm or

rule out the Rocketfish cable but found no qualified technical help there so I

kept the cable.


That's the condensed version of the story.


 


Note: UPS courtesy of Teamsters Union may be going on strike

July 31. Amazon depends on UPS. Plan your peripheral purchases accordingly.


 


Will keep the resolution at "2K" 120Hz due to

eyesight issues and 4k communication issues with cable - for now anyway.


 


Update:


 


Re: the Energy Saver put Studio to sleep feature - when it

kicks in it is difficult to re-establish communications between Studio and TV.

On for 2 seconds off for 2 seconds alternating after hitting the spacebar key

to get the login prompt.

 


Most likely an operating system issue with Ventura per 120Hz

setting?


Secondarily an issue with the cable?


Anyone with a better cable having my issue? If  no then what brand of cable are you using,

length, price and from whom?


Jul 25, 2023 8:50 AM in response to Jim Wainscott

Update:

The issue in Ventura appears to be with the sleep mode function, so:

In Apple icon > System Settings > Lock Screen I set the following parameters as follows:

Start Screen Saver when inactive: For 1 hour

Turn display off when inactive: Never

Require password... : After 1 hour


Step 1

Shut down the Studio

Power off the TV via remote.

Step 2

Power back on TV

Power on the Studio

If step 2 is done within a few seconds of step 1 Ventura recognizes the TV.

If step 2 is done the next day after step 1 Ventura recognizes the TV after a minute has passed.


In Displays Ventura recognizes the TV as LG TV SSCR2 and not the actual model number of the TV.

Display is stable at 4K 120Hz.

Again the issue in Ventura appears to be with the sleep mode function.


Sep 20, 2023 2:41 PM in response to ngerbens

In my LG user manual for the Gen 3 (ieC3) OLED TV it says it remembers the last input you set the TV to. I learned after trial and error to power on the Mac Studio within 1 second after powering on the TV (in that order). The TV will initially complain it has no input then (sometimes you have to wait roughly a minute but most of the time a few seconds) after it displays what input it is set to (hopefully from the Mac) will you then see the password prompt for the Mac.


Note: If my TV does not "see" any signal from the Mac it will automatically go to the default TV mode.


The cable length I am using is 4 feet due to the data rate required for 4K. I am not sure what length one can get away with. You can try using your present HDMI and the above first paragraph before parting with 50 euros.


Hope this helps!


Warning - LG loves to push frequent "updates" which maybe can cause an issue in communications with the Mac. I try to opt out of the updates but not always successful.

Ventura 13.4 gives no 120 hz option for external LG 4K OLED TV used for main monitor

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.