Using an LG 31MU97Z display with a Mac Pro late 2013

The Mac Pro late 2013 drives up to six displays, all on the same display card. That card is not over-taxed by doing so.

By design, the second card is left completely free to do GPU computing.

When Anandtech did their initial review, they pointed out that a GPU doing computing, that must also handle mundane screen re-draw duties, was severely handicapped. After each re-draw activity, the GPU computing that was interrupted has to be re-started. GPUs are particularly bad at being interrupted and re-starting.

Hi Susanna,

My Mac pro is Late 2013

2.7GHZ 12 core Xeon E5

64 GB

AMD FirePro D700 6144MB

My Thunderbolt connection is a Corning 18' passive (unpowered) cable.

I have the LG U95 thunderbolt 34 inch Display. Works ok but I use it with an apple 27 inch TB Display.

4K at 34 inched is going to be smallish and difficult to see or read text let alone icons. I had some 4K Displays and they just did not get it for every day use because the resolution is too small. I bought the U90 because compared to the Apple 27 inch Display its wider but height is the same and runs as does the Apple Display 2560 x1440 and the LG 3440x1440 nice and wide lots of room and easy to read for my eye sight.

As a stand alone thunderbolt Display I'd most likely not go for it. It works but with some issues. So I use the Apple Display as a thunderbolt hub and a boot display which is a big deal. The LG goes into hibernation mode too early and in some boot sequences will not mount to the Desktop. In a 'normal' environment it will. That hibernation mode means any TB device connected to its second port most likely is nothing to boot. The USB3 port is not going to boot an external.

As far as managing the arrangement I set the LG for main with file management BUT and its a big but Mavericks handles the arrangement perfectly. Yosemite crucifies it to the point I will not run Yosemite with the dual set up and EC handles it ok except for Desktop pictures rotation. I have to manually check box it every restart, not a big deal but needs fixed by Apple. Why am I concerned about the Desktop rotation of images to lessen possibility of screen burn in on both Displays.

So if you run your system as how mine is you'll like the LG. Running it singly maybe you won't but its doable. I don't think the Engineers at LG thoroughly understand the TB firmware required to make things happen correctly. That hibernation which is "going to low power mode" has to be considered. Bottom line I really like this LG anti glare Display compared to the glossy Apple Display but with certain draw backs. Its not an all in one Display solution. that split screen mode I could not stand it. Display gets split in two evenly with a red border around each split but all the windows will open where you can control their location. I turned it off.

This should help you decide. As far as using a Display wit mini display port to display port cabling its too hit and miss for things to work properly. Its a gamble.

Thanks for the Mac Pro spec Steve,

My... That is one Awesome Spec'ed out Mac Pro you have there! The 6GB graphics card may be swinging it for you to work? Not sure yet. I'm going to speak to Apple Support tomorrow morning about this and see if I can make some progress there...

Interesting point Grant. Thanks for the information!

Sounds like 2 x 2GB is really 'bear bones' these days if one of the cards is all but un-unitlised.

I have no idea if its possible to upgrade the graphics card(s) in the late 2013 Mac Pro model or not. Something I may have to think about much sooner than I expected (I only purchased this Mac Pro in Sep 2015!).

Appreciate your commenting 🙂

A quick update on the repalcement Thunderbolt cable from Apple - this works fine at full DCI 4K resolution @ 60Hz. The Mac Pro doesn't appear to like switching between computers however (this causes an issue in the monitor not being stable at 4K) but the lead itself appears to provide stable DCI 4K video at 60Hz as long as you are not switching between two computers on different inputs. The Thunderbolt cable was on its own bus to avoid any issues with bandwidth sharing (so nothing in the other TB port on the same bus No.2 slot #4).

Sounds like you've gotten it working. Good news.

you should pay more attention to the ASP assignment of those thunderbolt displays and I'd think display port connected. You want to observe in ASP under thunderbolt that the main and secondary display are broadcast at the top most level. That would mean separation of the bus. Also means bus 0 use port 6 and bus 2 use port 4. that way your observed routing string will become 1 and all will be more easily recognized during boot and use. Try it you'll like it. Bus 1 would be port 3. Will eliminate all those odd goings on you've been noticing.

I have a Mac Pro mid 2010
2.4 8-Core Mac Pro MC561LL / A
with geforce 770 (MacVidCards)
I purchased the monitor LG 31MU97 March 16, 2016
I'm working to 4096x2160 @ 24Hz
HDMI to HDMI you work at 4096x2160 @ 24Hz
With the actual cable 4Kx2K the display port working at 4096x2160 at 50 Hz
But the sound I can not make it work, in System Preferences> Sound, HDMI can not find it, I tried to install "HDMIAudio-1.0.dmg" with the terminal but in the end is not accepted