late 2013 Mac Pro and Samsung 4K U32D970Q Problems

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late 2013 Mac Pro and Samsung 4K U32D970Q Problems

I'm at my wits end. I really wish 4K displays were truly plug-n-play with new Macs.

I purchased a Samsung 4K U32D970Q from Amazon due to a couple positive reviews from users stating it works with their 2013 MP. It's a beautiful screen, much better uniformity than the LG 4K I sent back but it has a huge problem with random flickering. And by flickering I mean while watching videos, scrolling a website quickly the screen distorts and "blinks/flickers" momentarily then goes back to normal. I've tried a different DisplayPort>mDP cable along with the provided cables and same issue. The monitor is running SST at 60Hz.

You can see a video I made showing the blinking/flicker http://youtu.be/Rj8QwgzogqQ

This is actually my 2nd monitor as I did an exchange with Amazon same issue. I tried to contact Samsung and what a joke that support is. I get a guy who said he has no idea then sent me a firmware update list... that hasn't been updated since last March. No help.

I've already reset pram and smc, tried different TB ports without any luck.

Is it just wise to stick to the officially supported, and very expensive, list of 4K monitors or go QHD and wait for the 2016 MP for true 4K+ support?

Posted on Jan 14, 2015 4:31 PM

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Answer 1

Jan 14, 2015 8:33 PM in response to DaveDub79

Generally speaking, there is too much data to run 4K at 60Hz without enabling Multi-Stream Transport using the display's internal settings.

DisplayPort is a somewhat different protocol from previous ones. Only the changed data are sent. When the screen changes its contents rapidly, as you have demonstrated, there is not enough bandwidth in Single Stream Transport to keep up -- there are simply too many bits. Different screens will react to the 'not enough data' in different ways -- this screen seems to flicker.

If your screen supports Multi Stream Transport, enable it in the display's Menus. Otherwise, change it fast and it cannot possibly keep up.

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Answer 2

DaveDub79 Author

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Jan 15, 2015 6:43 AM in response to Grant Bennet-Alder

Thank you for the reply. Everything you're saying makes complete sense but my confusion comes in from people running these on Windows machines over display port without any issues. Is it just Apple's handling of Displayport + 4K? I know older 4K used MST but these newer panels run on SST. I couldn't find any MST settings in the monitor's OSD.

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Answer 3

lllaass

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Jan 15, 2015 7:45 AM in response to DaveDub79

I would also post in the MacBook Pro laptop forum. This is the Mac Pro desktop forum.

MacBook Pro

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Answer 4

DaveDub79 Author

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Jan 15, 2015 8:01 AM in response to lllaass

Why exactly? My machine is the late 2013 MAC PRO as stated in the subject of the thread. It's not a Macbook...

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Answer 5

lllaass

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Jan 15, 2015 8:18 AM in response to DaveDub79

Sorry about that

Page 16 of the manual, page 16

http://downloadcenter.samsung.com/content/UM/201408/20140825091544728/BN46-00430 A-Eng.pdf

says:

― When an HDMI cable is connected, the product can display UHD resolution

(3840x2160 @ 30Hz).

Have you tried using a display>mini displayport 1.2 cable and selecting DP 1.2 in settings See page 73 of the manual.?

I had to do that with my Dell 24" 4K monitor to get 4K at 60Hz. With DP 1.1, default, I only got 30 Hz

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Answer 6

vortimac

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Jan 15, 2015 10:17 AM in response to DaveDub79

This combination is fully capable of running 4K at 60hz using SST - the bandwidth required is well below what DisplayPort 1.2 provides.

I have a 2013 Mac Pro driving this same display, and it does not exhibit the flickering shown in your video while watching videos or scrolling pdfs. Based on the fact it's done this with two different monitors, that would seem to say it's an issue with your particular Mac Pro.

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Answer 7

DaveDub79 Author

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Jan 15, 2015 10:24 AM in response to lllaass

Illaass: Thanks actually this monitor defaults to DP 1.2 being on so that wasn't it unfortunately.

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Answer 8

DaveDub79 Author

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Jan 15, 2015 10:24 AM in response to vortimac

Vortimac: Do you have the base model with D300? I've seen people have luck with the upgraded D700s but no one else with the base D300s. I thought it was a hardware issue but I've tested the LG 4K 31MU97-B monitor and it didn't have any of these issues but rather horrible color uniformity so I returned it for the Samsung. Also my old 27in NEC display has no graphic issues either.

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Answer 9

lllaass

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210,471 points

Jan 15, 2015 10:29 AM in response to DaveDub79

I suspect a hardware problem. I would make an appointment at the Genius Bar of an Apple store.

Apple Retail Store - Genius Bar

However, first I would clone the current installation to an external HD and then do a fresh install of Yosemite and see if you still have problem. The Genius will likely require that.

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Answer 10

vortimac

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Jan 15, 2015 10:38 AM in response to DaveDub79

I have the D500. Right, if the LG monitor was working at 4k, that is curious.

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Answer 11

DaveDub79 Author

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Jan 16, 2015 4:20 PM in response to vortimac

Possibly good news! I found this thread about creating a custom override file for a monitor and I've successfully tricked OS X into thinking this is a 56Hz screen. Mac Pro Late 2013 and Samsung 4k monitor problem

So far it starts up at 56Hz and all the HiDPI scaled sizes are working without the flickering. Before I could create a 56Hz custom resolution in SwitchResX but none of the scaled were they all defaulted to 60Hz.

I'm going to keep this going for a day or two and see if everything stays the same. Honestly there's barely any difference between 56 and 60hz to my eyes.

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Answer 12

DaveDub79 Author

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Jan 16, 2015 4:54 PM in response to DaveDub79

Quick update the hack worked but it now thinks my monitor is the 27.1 in Samsung from my link above. The good news is that I was able to select the color profile from my list (the one from the link is standard gamut so everything looked horrible). I'm going to see if I can someone to explain how to change the display override file so it still thinks my monitor is the 32in Samsung.

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Answer 13

DaveDub79 Author

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6 points

Jan 17, 2015 11:39 AM in response to lllaass

I took your advice to setup a Genius appointment but they stopped me at higher tech support over the phone. I was told that because my current NEC 1920x1200 display, and the LG 4K cinema I returned, don't have any issues it's not my D300 gfx cards. He said bringing it in would only verify that so it'd be a waste of time.

I was then told to return it, we can't officially guarantee 3rd party compatibility etc etc. So sadly my saga with the Samsung is coming to a close. It's seriously the most beautiful screen I've ever used (no dead pixels, only slight contrast lost at the extreme edges but no worse than my aging NEC) which is unfortunate because going back to a non-4K is depressing.

I'm either going to pick up a QHD NEC or a refurbished Dell 4k 32in from Amazon since they have them used for about $1200 right now. Thanks again to everyone for the help.

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Answer 14

Jan 26, 2015 4:25 PM in response to DaveDub79

I just wanted to add to this for anyone thinking of buying the U32D970Q to use with a Mac Pro (Late 2013) who might have been put off by this post, as I know when researching my purchase it almost stopped me ordering.

My U32D970Q arrived today and seems to be running perfectly with the 3.7 GHz Quad-Core, D300, I'm seeing none of the issues demonstrated in DaveDub79's video.

The only issue I'm having right now is some slow down when using the U32D970Q and two Apple Thunderbolt 27-inch Displays simultaneously, but that looks more like a software issue than a hardware problem.

My first impressions of the U32D970Q are very positive, if I have any issues I'll post back here, but for now it seems like a superb monitor.

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Answer 15

DaveDub79 Author

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Jan 26, 2015 5:42 PM in response to andrewkendall

I'm both happy and frustrated with your post! Glad it's working for you but beyond frustrated it won't with mine. Apple phone support told me since the LG I tried out (4K) and my current NEC 2690wuxi2 work just fine it's not my system. I may just make an appointment and haul it in for a repair/replacement if others are having luck. I really, really wanted to keep that monitor.

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