MP 6,1 6,1 Display Issue

[gbsharon]

Hi all!
Just got my quad core trash can with FirePro D300s. I’m setting it up right now with my Dell 49” ultrawide and having some issues. It looks like the resolution is super low and the machine is recognizing the monitor as double the size that it is.

As you can see in the photos, the dock and the top bar are only about 1/2 way on the screen. In the menu, it won’t give me an option to select a specific resolution just text size with a note under that says “Looks like” and then a resolution. I noticed one of those options has the correct resolution in it but does not make a difference when selected. Selecting different ones of these essentially just changes the text size on the screen.

I have confirmed the machine operates fine on a smaller monitor. It is driving the monitor through a brand new TB2 to display port cable. Any thoughts? Do I need to use one of those programs that spoofs the resolution and lets you enter a custom resolution? Is this one of those ultrawides that doesn't like to play nice with Macs?

TIA!

https://imgur.com/a/jxhfzI7

 

[tsialex]

AMD documentation says that the maximum resolution that a D300/HD 7870/R9 270 supports via Display Port is 4096 x 2160, while Apple says that a MP6,1 supports 3 5K displays, 5120 × 2880.

If you monitor is over 4096 x 2160, but less than 5120 × 2880, and you have a correct cable, you probably need to use an app like SwitchResX to set the correct mode needed by your display.

Edit:

MP6,1 only supports 5K Displays that use dual cables, MST displays.

• Three dual-cable 5K displays

 

[gbsharon]

Using SwitchResX, I am able to push to 3840 x 1080 without an issue, 59.88Hz without an issue. Any resolution selected after that results in the same problem. Any further recommendations for troubleshooting?

https://imgur.com/a/eW5PLBS

 

[chrfr]

The Mac Pro 6,1 can only do a full 5k through the extremely rare displays that use 2 input cables. Newer 5k displays like the LG will scale down to 4K.
With this Dell being 5120x1440, it may not work with the 2013 Mac Pro.

 

[tsialex]

The Mac Pro 6,1 can only do a full 5k through the extremely rare displays that use 2 input cables. Newer 5k displays like the LG will scale down to 4K.
With this Dell being 5120x1440, it may not work with the 2013 Mac Pro.

Yep, you are correct about MST. I just noticed it on the Apple spec sheet for late-2013 Mac Pro:

• Three dual-cable 5K displays

 

[gbsharon]

Think you're correct. The display has a dual input mode where it treats each 1/2 of the screen as its own individual screen so I'm running 1 side through display port and 1 side through HDMI to make 1 big screen at full resolution.

 

[saulinpa]

Did you try toggling spaces? https://discussions.apple.com/thread/250079605