Mac Pro Late 2013 and Samsung 4k monitor problem

Anyone tried switchresX on the mac pro 2013 and the samsung 4k? I'm going to give it a go tomorrow.. see if I can get displayport working at 2560x1440 rather than running 30Hz on hdmi. will let you know what happens.

The EDID of the Samsung monitor was posted on MacRumors. It does mention that it supports a 2560 x 1440 mode with the same parameters I listed. It also has a timing for 1920 x 1080 as well as the native 3840 x 2160.

It also lists frequency ranges which suggests it has a scalar that can support custom resolutions not listed here. In that case, you might try creating different resolutions and/or frequencies to find what limit (resolution or pixel clock or refresh rate) is causing the problem. Maybe it's an HBR2 problem? At what frequency does DisplayPort 1.2 switch from HBR to HBR2?

For resolutions: If 2560 x 1440 at 60 Hz works without problem, then you can try creating larger resolutions at 60Hz by adding multiples of 32 to the horizontal and 18 to the vertical (to keep the 16:9 ratio) up to 3840 x 2160. The reason to use 32:18 is because some drivers don't like odd number of vertical lines. You could try going beyond 3840 x 2160 to test if the monitor scalar can shrink the input. We already know that the graphics card scalar can shrink the output to support larger HiDPI modes.

For frequencies: If 2560 x 1440 at 60 Hz works without problem, then you could add other 2560 x 1440 timings by adding multiples of 5 Hz to the refresh rate up to the point where the pixel clock is 540 MHz or the refresh rate is 75 Hz.

Detailed mode: Clock 533.250 MHz, 607 mm x 345 mm

3840 3888 3920 4000 hborder 0

2160 2163 2168 2222 vborder 0

+hsync -vsync

Detailed mode: Clock 241.500 MHz, 607 mm x 345 mm

2560 2608 2640 2720 hborder 0

1440 1443 1448 1481 vborder 0

+hsync -vsync

Detailed mode: Clock 148.500 MHz, 607 mm x 345 mm

1920 2008 2052 2200 hborder 0

1080 1084 1089 1125 vborder 0

+hsync +vsync

Monitor ranges (GTF): 56-75Hz V, 30-134kHz H, max dotclock 540MHz

I just got the Seiki SE39UY04 and I would say that through HDMI at least with sharpness down the text isn't very smooth (seems like text smoothing isn't working, with sharpeness up it looks horrid). I noticed similar with my older monitor that if I used HDMI the text wasn't smooth. Anyone notice this? Will using this monitor through an active displayport make a difference like it did on my last monitor?

The other thing I noticed is that playing 4k can be dangerous! I played a 4k video a few times through quicktime and eventually my machine rebooted itself! 4k through FP is really jerky due to lack of hardware decode, I'll try to if something can be done 🙂

played about with it tonight using standard resolutions but nothing worked at hig res 60hz.. a couple of smaller res's worked at 75hz, so I think I have to play around more with the specifics and increment up in the custom mode... knowing how to use switchres properly will help so i'll have another go tomorrow and watch a tutorial first. not sure it was 'taking' my custom resolutions at all. so will figure that out and go again tomorrow

If SwitchResX says "modified" in the bottom right corner or the new timing says "Not saved" then press Command-S to save. Type in your password to save. Then if the new timing says "Needs to reboot" then you need to restart the Mac. After restarting, if the driver accepts the resolution/timing then it will say "Active", otherwise it will say "Not activated - invalid?".

Did the 2560 x 1440 timing not get activated? In the Current Resolutions tab, you can click a radio button for an activated resolution to use it, and you can double click it to see the timing information for it.

Ok, did as above with the settings you did a screenshot of before and got "Not activated - invalid?"... should I decrease the resolution until it accepts it and go from there...? it would be good to get displayport working at some sort of acceptable resolution 😟

Sure, try starting from 1920 x 1080 @ 60 Hz. Try CVT-RB and GTF. Enter a bunch of sizes or refresh rates, then restart to see which if any get activated. If nothing works, then maybe you can try overriding the EDID to remove the 3840 x 2160 descriptor and/or make the 2560 x1440 @ 60 Hz descriptor the first one.

I wonder how digitalcoleman got 2560 x 1440 to work. Are you sure there's no 2560 x 1440 @ 60 Hz mode already (non-scaled)? Maybe digitalcoleman used an HDMI cable for that since it only requires 241.5 MHz.

Anyway, send a screen shot of the Current Resolutions and Custom Resolutions tabs of SwitchResX to show us what you've tried. Post the EDID info if it doesn't match the info posted in the MacRumors forums.

http://forums.macrumors.com/showthread.php?t=1668673&page=4

Hi ttppee, I too had purchased a pair of PB287Qs only to discover the 56Hz and tearing along the right edge problem. I submitted a bug report to Apple and luckily, they have responded asking me to provide some additional data - hopefully it will lead to a solution! Unfortunately, I have since returned the monitors so I cannot provide that data. If you are able to get me these files, I'll gladly submit them and hopefully we can all receive a fix from Apple. Thanks!

This is a courtesy email regarding Bug ID# 17378711.

Please update your report directly at http://bugreport.apple.com for the fastest response. Please do not email your updates.

Engineering has requested the following information in order to further investigate this issue:

Please attach the output of 'sysdiagnose' collected while the problem is occurring or if not possible taken after the issue has occurred. 'sysdiagnose' can be triggered by pressing Cmd-Opt-Ctrl-Shift-Period, and it may take a few minutes to complete. When ready, the output will automatically be revealed in a Finder window (or it can be manually retrieved from /var/tmp)

Also, please include a full System Information Report.

To obtain a full System Information Report on OS X:

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4. Select "Save…" from the File menu (cmd-s)

5. Change the file name and save location as needed

6. Click the "Save" button

A System Information Report can also be obtained via Terminal using the following command:

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Then they'll ask you to send them a timing file, and then they won't talk to you any more.

Look at bug report

16937706

for the exact same issue.

Interesting. I have a New Mac Pro with D300s (low end), and the PB287Q and don't have this problem. Everything actually works great on 10.9.3, 4k and 60hz.

The only thing I did was activate display port 1.2 in the monitor settings (otherwise it was stuck at 30hz).

Maybe this is an issue with the D700s? Someone in a different forum with D700s reported the same problem.

Hi Terscion,

Thanks for your information, I am in a business trip now, I will try as soon as I back to home!

I have a the UD590 and a Mac Pro late 2013 with the D700s. I am seeing this issue as native resolution as well. It also doesn't turn on after sleep sometimes and I recently caught it blinking in and out like crazy. The blinking and not waking up requires a power cycle to fix. Early adopter for life!

That said, there are a number of D700 GPU issues introduced with 10.9.2 and 10.9.3. There is a new 10.9.4 beta release that clears up the multi monitor issue with the Mac Pro. Could be worth a shot to try the 13E19 beta. I don't want to sign up for a $99/year plan just to test it though. 😝

I had a similar problem with MacPro4,1 and a AMD7950 on the Samsung 4k. I did discover that dropping the refresh rate to 50Hz would result in no artifacts. 55Hz still gave some, but less. My understanding is the nMP is using the same drivers, so the same fix might work if you're willing to live with a slight refresh drop. I used SwitchResX to make the mode, though I'm sure there's other ways.

My bigger problem was the system would not boot with the monitor attached to the 7950's displayport, so I swapped to a GTX 680 which works fine (as others noted)

Can you share what settings you're using to get 50Hz?

Also, I'm trying 10.9.4 Beta 13E19 and it doesn't fix the Samsung distortions on the right side at 60Hz. It does fix multi monitor bugs (more than 3 screens at the same time).

I'm not 100% positive of the settings, since I don't have the AMD card anymore. But I'm pretty sure all I did was create a custom resolution CVT-RB simplified settings w/ a 50Hz refresh rate, leaving the default settings for horizontal sync (pos) and vertical sync (neg). Then save, reboot, and use SwitchResX to select the new 50Hz mode.

You might need to create the scaled resolutions if you want 50Hz versions of the lower resolutions (hidpi) - I just run mine at native, so I can't remember the steps involved, though I remember something about having to create 2x resolutions of each resolution you want. There might be more info at the switchresx website or forums....

BTW: Does the nMP give a boot image on a 4k single-stream monitor?