Quick question on LG LG 31MU97 display

Peeetski

macrumors member
Original poster
May 14, 2014
41
26
Hi all!

My work has been getting a little too cramped on the laptop screen so I've decided to get a new display for work stuff. I've done a bit of reasearch and I think the LG 31mu97 seems to be a pretty good one. Just wondering, though, I saw a few posts mentioning a Z version or a Thunderbolt version.

I was looking at this -
http://www.scorptec.com.au/product/Monitors/25plus-inch/56604-31MU97
My laptop is a mid 2015 with AMD.

Does that seem right? I don't want to grab it and find out later I should have grabbed a slightly different version.
Just wondering if anyone has any advice about this??

Thanks,
Pete
 

Peeetski

macrumors member
Original poster
May 14, 2014
41
26
Yeah, I guess I'll give it a try at the place first.
In the description it says for a mac, you should use Mini DisplayPort to DisplayPort which apparently is capable of 4096 x 2160 @ 60Hz.
 

Peeetski

macrumors member
Original poster
May 14, 2014
41
26
Okay I grabbed this monitor and it's a great, but... OSX has some weird limitations that bring it down.
It can only do the highest possible res, no HiDpi modes or lower resolutions are available so that's a bit of a bummer... I have no idea why it can't do any of the lower res modes!? So the fonts (in OSX) are super tiny and cause a bit of eye strain. I just find myself reverting back to the laptop often :(
 

itdk92

macrumors 6502a
Nov 14, 2016
501
180
Copenhagen, Denmark
Okay I grabbed this monitor and it's a great, but... OSX has some weird limitations that bring it down.
It can only do the highest possible res, no HiDpi modes or lower resolutions are available so that's a bit of a bummer... I have no idea why it can't do any of the lower res modes!? So the fonts (in OSX) are super tiny and cause a bit of eye strain. I just find myself reverting back to the laptop often :(
Grabbed the same monitor a few days ago.

My conclusion is that the monitor can be run in the following configs:

4096x2160@50hz

2048x1080@50hz (HiDpi)

to enable the 50hz you need to
- connect the monitor
- enable display port 1.2 in the monitor settings
- go to display preferences in your macbook pro 15" 2015
- option click on "scaled"
- click on "show lower resolutions"

and then you can choose the one you want between the two.

For some weird reason, all the HiDpi scaling between 4096x2160 and 2048x1080(hidpi) are not supported, and this makes the monitor pretty useless

I am only waiting to see if my classic mac pro with a RX480 will drive it properly, otherwise I will return it. Such a shame
 

Peeetski

macrumors member
Original poster
May 14, 2014
41
26
Hey itdk92,

Thanks heaps for letting me know about that other working res! That's kinda nice for when my eyes are not ready for the crazy max res :D. It sucks apple don't really support it, especially since they don't really offer an alternative.
My windows machine works great with it, but you know... it's windows :).

If you do end up bailing, let me know what alternative you go with.

Thanks,
Pete
 

itdk92

macrumors 6502a
Nov 14, 2016
501
180
Copenhagen, Denmark
So did it show the fonts bigger or still everything is very small ?
Im looking to buy it, but confused.

I actually have it because it then worked flawlessly with my cMP 5.1 with all the modern GPUs I have tried out.

Only thing is I bought switchresX to make custom hidpi res which I actually could use :)
 

itdk92

macrumors 6502a
Nov 14, 2016
501
180
Copenhagen, Denmark
Confused. So basically connected and then use the app ? Can I have a full screenshot of your display ?
I will post a screen later tonight.

Basically, it's clearly AMD drivers that are the issue here. Older 15" or as such older graphic cards have no problem whatsoever unning the card.

The software is needed because the standard macOS HiDpi resolutions were very limited and limiting.
 

Peeetski

macrumors member
Original poster
May 14, 2014
41
26
So did it show the fonts bigger or still everything is very small ?
Im looking to buy it, but confused.
Just to throw in my two cents, the monitor itself looks great but, it is limited to the two configs mentioned earlier (at least on my gen macbook pro - Mid 2015).
4096x2160@50hz
2048x1080@50hz (HiDpi)
I went for 2048 because the higher one was straining my eyes, but it's a shame it couldn't run the full res with some font scaling.

It feels kinda barely supported though, like when you plug it in at first it just goes black and you have to hold alt to get these other hidden resolutions that it might work with.

I decided to stick with it though because it works great with my pc, and it'll probably work better with future macs I end up with.

P.
 

itdk92

macrumors 6502a
Nov 14, 2016
501
180
Copenhagen, Denmark
So basically there are two things with this monitor:

1st problem is compatibility - very few macs can run it, because of very poor DP 1.2 drivers from AMD side

2nd problem is that if you actually succeed in making it work, the resolutions are limited to
4096x2160@50hz <-------- things are way too small
2048x1080@50hz (HiDpi) <-------- things are kind of big,

That's why I have bought SwitchResX (I am not affiliated in any way - it's just the only one which worked for me)

With SwitchResX I made the custom resolutions in the screenshot below, which are great to work with (but may be a little heavy on some macs's GPU)
 

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