LG 31MU97 4K Display not showing 4K on MacPro

Just to add to this discussion, with a late 2013 Retina Macbook Pro running 10.10.1 & an NVIDIA GT750M video card, I am able to go to 4096x2160/50Hz if I hold down the Option(Alt) key and click on Scaled in Display Preferences:

Otherwise 3840x2160 is the max resolution visible.

The monitor quality is very nice, but it seems awfully wide at first use... hopefully I'll get used to it. I'm a little concerned because I'm starting to see a bit of flickering off to one side of the display (like a quick twitch but only half the screen).

Just got this monitor setup on a mid 2014 15' Retina MBP using the display port cable that came with the monitor. Did a test at http://www.testufo.com/#test=framerates and show 50hz

Quick followup to my first message - the flickering was all due to a third-party DisplayPort cable I had bought because I thought the cable included with the monitor would not drive the full resolution - in fact the original cable has been just fine, with zero flickering. Still the full resolution at 50Hz.

OK- scratch that! I just rebooted the computer for the first time after having it on for 12 hours and I can longer go over 3840x2160 30hz. It was working at 4096 out of the box. Not sure what happened. Anyone else experience this?

http://forums.macrumors.com/showthread.php?t=1811376&page=15 post #366 seems to highlight the issue i have.

I havent tried this display with Yosimete but Im hoping the OS update will get rid of this:

This is caused by the 60Hz setting (SwithResX as well).

HDMI is limited to 30Hz.

If you can, connect directly with a DisplayPort family cable, as no conversion is needed and data rates and refresh rates supported are much higher.

Yes that I know.
Fixed it for now with Yosemite upgrade.
However this display is for Avid and Pro Tools studio so hoping updates on both apps soon.

Visual glitches: I have that and more!...

4096x2160@ 60Hz SST is now official / supported: great!? No!

With yosemite 10.10.2 it was working fine at 50Hz, now with 10.10.3, 60 Hz is forced: the result is visual glitches and (more annoying) everything turning to black most of the time!

With alt+scaled+show lower resolution: 50Hz could be selected (when the screen is not black! ;-) but only for max resolution; scaled resolutions are 60Hz only! (why!?)... Also when booting it's in 60Hz: unusable.

I probably either have a bad graphic card (Mac Pro D300), a bad (LG supplied) thunderbolt-display port cable, or a bad monitor unit (bought in Switzerland where power is at 50Hz btw); but it's too bad that we don't have an easy way to throttle down the refresh rate!

'waiting for a new cable, meanwhile I've turned off display-port 1.2 on the monitor itself (so is 1.1): I can use the screen in 3860x2160 (scaled "as" 3008x1692) at 30Hz! without too much mouse lag!

Is there a way to use the EDID?, "driver"? from 10.10.2 instead? I don't want to revert my whole OS to 10.10.2, if it doesn't work with a better cable I'm gonna trash this monitor.

(with a new mini DP to DP cable, it's not better)

I reverted to OS-X 10.10.2 (recovery a from a Time Machine backup), all is fine again: 4096x2160 @ 50Hz !

So, I'm stuck with 10.10.2!

It seem that I'm the only person in the world that want 50Hz instead of 60Hz! (frankly it's probably impossible to tell the difference) but having the choice would be nice: if your particular monitor unit doesn't work well at 60Hz (btw in the user manual the specified default preset is 4096x2160 @ 50Hz). Obviously my monitor / cable failure is not Apple fault but it's annoying to send for repair or trash a monitor that works fine in a mode that suits you! So it's really annoying that there is no way to force / throttle down from 60Hz to 4096x2160 @50Hz (in DP 1.2, when booting or for scaled modes) on 10.10.3...

Hi,

I'm thinking about buying this monitor and I wonder if the latest version of the OS can run this screen (without visual glitches) at 4096x2160 @ 60 Hz. After reading the whole thread I'm not fully sure that it's fully working yet or not.

I got a Mac Pro (late 2013)

Cheers!

Have you read this? It has been updated since this discussion was started

Using 4K displays and Ultra HD TVs with your Mac - Apple Support

Hi,

Thanks for the reply. That page state that

"With OS X Yosemite v10.10.3, most single-stream 4K (4096x2160) displays are supported at 60Hz operation on the following Mac computers..."

It states "most single-stream" and I just wonder if the LG 31MU97 is one of them?

Cheers!

yes the LG 31MU97-B is supposed to work a 4096x2160 @ 60Hz on OS-X, BUT some/many? have problems/defects like mine (was working fine at 50Hz but not at 60Hz, enforced after upgrading to any OS-X version greater than 10.10.2). p.s. maybe that's why LG now lists a 31MU97-Z ?

In the end I send it for repair (p.s. in Switzerland, LG service/repair is not directly handled by LG but "outsourced" to a small company named Repag), they changed the "main-board" and now it's working flawlessly (so far! 'received it few hours ago!) under OS-X 10.11 "El Capitan".

So, as long as your cable is decent (I'm using an Accell mini-DP to DP cable, but the included one should be fine), on a (clean) OS-X >10.10.2 install, at 4096x2160 @ 60Hz if the screen is turning to black, or showing artifacts: it is likely "faulty": have it fixed

OMG, updating to EL Captain finally allowed me to use 4096 x 2160 native resolution on my LG 31MU97 monitor with a Macbook Pro 13" Early 2015 rMBP. I've been waiting for this day for a long long long time.