MP 6,1 Mac Pro 6,1 and modern 5k monitor

[robertosh]

Hi folks,
I'm pursuing a nice offer for a mac pro 6,1 for 490 EUR: 4 core xeon (plan to update it with the 12c) and 32G RAM. My plan in near future would be to pair it with a DELL U4021QW, which has a resolution of 5120x2160. Do you think that the mac can run that monitor at 60hz? I've read that i would probably need to use the thunderbolt ports as the hdmi is only 1.4, but that does seem a problem. Monitor also have thunderbolt, but probably the one in the mac pro is way older.. Anyone has recent success/failure histories with 5k monitors and this mac?

Thanks!

 

[SpotOnT]

I am not very family with ultrawide displays (and I am sure someone will correct me if I say anything wrong), but my understanding is the Mac Pro doesn’t support resolutions above 3840x2160 with a single cable.

If you want to go with 5k or 5k ultra-wide, you need a dual link displayport monitor….and I don’t think anyone makes those anymore.

 

[robertosh]

oh, thanks a lot. At first, i was thinking that a 2-mini-display adapter was needed, but is the actual monitor the one that that needs to have 2 display port. Now everything is explained... Thanks again, will consider my purchase!

 

[joevt]

MacPro6,1 can't do 5K width to a single cable display. You could create a custom timing to do it - maybe with a lower refresh rate to fit in the HBR2 link rate limit, but the old AMD graphics cards have strange artifacts when the width > 4096.

Some 5120x2160 displays (LG 5K2K) have a dual link SST mode using two DisplayPort connections over Thunderbolt 3 but you can't do that with a single Thunderbolt 2 connection.I don't know if the Dell has a similar dual link SST mode. I don't know if the Dell or LG are smart enough to take dual DisplayPort from different ports - one from DisplayPort and one from USB-C.

If you can't do dual tile display mode (where the tiles act as a single display), then you might try Picture by Picture mode if it exists. This is where the display behaves as two 2560x2160 displays.

If dual link SST can only be done with Thunderbolt 3, then one option is creating a Thunderbolt 3 signal using a Thunderbolt 3 add-in card which might require flashing the card or injecting an SSDT using OpenCore - and even then it might not work. A simpler option is to use an eGPU with downstream Thunderbolt 3 port such as the BlackMagic eGPU or the Sonnet eGPU Breakaway Puck RX 5500 XT/5700.

 

[joevt]

Some 5120x2160 displays (LG 5K2K) have a dual link SST mode using two DisplayPort connections over Thunderbolt 3 but you can't do that with a single Thunderbolt 2 connection.I don't know if the Dell has a similar dual link SST mode. I don't know if the Dell or LG are smart enough to take dual DisplayPort from different ports - one from DisplayPort and one from USB-C.

If you can't do dual tile display mode (where the tiles act as a single display), then you might try Picture by Picture mode if it exists. This is where the display behaves as two 2560x2160 displays.

I looked at the Dell Display's User Manual. It doesn't appear to have a dual HBR2 over Thunderbolt 3 mode like the LG does.

Maybe the graphics drivers in macOS can be changed to make the two displays presented by PBP mode behave as two tiles of a single tile display. I am working on a patch to do that. I haven't tried it yet. I don't know if it will work. How it would work is, you enable the patch, connect USB-C and DisplayPort to the Mac, and enable picture by picture.

 

[robertosh]

MacPro6,1 can't do 5K width to a single cable display. You could create a custom timing to do it - maybe with a lower refresh rate to fit in the HBR2 link rate limit, but the old AMD graphics cards have strange artifacts when the width > 4096.

Some 5120x2160 displays (LG 5K2K) have a dual link SST mode using two DisplayPort connections over Thunderbolt 3 but you can't do that with a single Thunderbolt 2 connection.I don't know if the Dell has a similar dual link SST mode. I don't know if the Dell or LG are smart enough to take dual DisplayPort from different ports - one from DisplayPort and one from USB-C.

If you can't do dual tile display mode (where the tiles act as a single display), then you might try Picture by Picture mode if it exists. This is where the display behaves as two 2560x2160 displays.

If dual link SST can only be done with Thunderbolt 3, then one option is creating a Thunderbolt 3 signal using a Thunderbolt 3 add-in card which might require flashing the card or injecting an SSDT using OpenCore - and even then it might not work. A simpler option is to use an eGPU with downstream Thunderbolt 3 port such as the BlackMagic eGPU or the Sonnet eGPU Breakaway Puck RX 5500 XT/5700.

Thanks for the detailed answer. I will probably go for the Mac as it seems a good deal. I’ve thought about the eGPU as well, but the Mac has thunderbolt 2, not sure if that would be a bottle neck. I’ve already played with Opencore, but I would prefer something more straight-forward and less hacky. The idea is to have the Mac for music production.

 

[robertosh]

MacPro6,1 can't do 5K width to a single cable display. You could create a custom timing to do it - maybe with a lower refresh rate to fit in the HBR2 link rate limit, but the old AMD graphics cards have strange artifacts when the width > 4096.

Some 5120x2160 displays (LG 5K2K) have a dual link SST mode using two DisplayPort connections over Thunderbolt 3 but you can't do that with a single Thunderbolt 2 connection.I don't know if the Dell has a similar dual link SST mode. I don't know if the Dell or LG are smart enough to take dual DisplayPort from different ports - one from DisplayPort and one from USB-C.

If you can't do dual tile display mode (where the tiles act as a single display), then you might try Picture by Picture mode if it exists. This is where the display behaves as two 2560x2160 displays.

If dual link SST can only be done with Thunderbolt 3, then one option is creating a Thunderbolt 3 signal using a Thunderbolt 3 add-in card which might require flashing the card or injecting an SSDT using OpenCore - and even then it might not work. A simpler option is to use an eGPU with downstream Thunderbolt 3 port such as the BlackMagic eGPU or the Sonnet eGPU Breakaway Puck RX 5500 XT/5700.

Ah, thanks for the LG information, I was also considering that one thanks to the higher dpi.

 

[Seiko4169]

I have the 6’1 and a black magic EGPU connected to LG’s 49” ultra wide. At the native monitor res it’s great but without the EGPU the reduced res isn’t very pleasant. Realistically I should pair the 6’1 with a nice 4K and ditch the egpu. The 6’1 is a brilliant piece of engineering that impresses as soon as you slide the cover and peek inside! Trying to push it into the more extremes doesn’t suit its age.

 

[ironmanny1]

I have a Mac Pro 6,1 with an LG 5k Ultrafine (27MD5KL-B)
monitor running Monterey. I have a thunderbolt 3 to Thunderbolt 2 adapter from apple and connect it directly to my Mac. I am able to get the 5k resolution.

 

[SpotOnT]

I have a Mac Pro 6,1 with an LG 5k Ultrafine (27MD5KL-B)
monitor running Monterey. I have a thunderbolt 3 to Thunderbolt 2 adapter from apple and connect it directly to my Mac. I am able to get the 5k resolution.

Your graphics cards are rendering in 5k. Your screenshots will be in 5k. But Thunderbolt 2 doesn’t have the bandwidth for 5k. So what is happening is your GPU is rendering at 5k, transferring at 4k, then the monitor is upscaling to 5k.

So really you are getting upscaled 4k on your 5k display. There are a lot of threads on this, if you want to poke around a bit.

 

[joevt]

I am able to get the 5k resolution.

macOS only reports the framebuffer size. It does not report the output resolution. Use SwitchResX to view the timing info of the current resolution. It will say: Active pixels 3840x2160 Scaled to 5120x2880.
Perhaps you've never seen real 5K before and therefore didn't notice that your 5K display is blurry.

 

[ironmanny1]

macOS only reports the framebuffer size. It does not report the output resolution. Use SwitchResX to view the timing info of the current resolution. It will say: Active pixels 3840x2160 Scaled to 5120x2880.
Perhaps you've never seen real 5K before and therefore didn't notice that your 5K display is blurry.

Thank you for the reply, When I have an Apple Thunderbolt Display next to it, the LG looks pretty sharp =).

 

[joevt]

Thank you for the reply, When I have an Apple Thunderbolt Display next to it, the LG looks pretty sharp =).

True, 4K > 1440p. But 5K > 4K which is what you're missing.

 

[mikas]

You can use that particular Dell monitor model in PbP (Pictur by Picture) mode with any of the 6,1 variations (D300, D500, D600). Attach Mac Pro with two signal cables to the Dell. Switch on the PbP mode and choose from the available divide ratios.
Jan 14, 2022
Jan 14, 2022
At least the 50/50 (2560x2160 + 2560x2160) and 75/25 3840x2160 + 1280x2160) divide ratios are supported by 6,1 GPUs. I think I managed to try and use "true" 4K too, 80/20 ratio, which means 4096x2160 + 1024x2160. But not sure, that might have been with 4K 4096 with TB2toTB3 eGPU + D300 at 1024. It's easy to test though.

 

[Amethyst1]

I’ve thought about the eGPU as well, but the Mac has thunderbolt 2, not sure if that would be a bottle neck.

I run an eGPU on a Thunderbolt 2 Mac for exactly that reason: to get around resolution and pixel clock limits imposed by the internal GPU. It works just fine. Yes, Thunderbolt 2 bottlenecks the eGPU during e.g. gaming but this isn't what I use it for.

 

[arw]

I run an eGPU on a Thunderbolt 2 Mac for exactly that reason: to get around resolution and pixel clock limits imposed by the internal GPU. It works just fine. Yes, Thunderbolt 2 bottlenecks the eGPU during e.g. gaming but this isn't what I use it for.

You don‘t by any chance use Photoshop? I ask because my MP6,1 performs better overall with an eGPU (RX 570) connected to a 5K display. But in Photoshop, moving the canvas is really choppy (like 5 fps) compared to the internal D300 (also at 5K via dual DP). I can‘t imagine this being a bandwidth issue? GPU acceleration in Photoshop is working and processing is indeed faster.

 

[Amethyst1]

You don‘t by any chance use Photoshop?

No, sorry.

 

[vddobrev]

Just go with a nice 4K display instead. The MP6,1 will handle it fine.