MP All Models AMD Radeon RX 6800 XT / 6900 XT for macOS?

[avkills]

And I was beginning to think I was the only one insane enough to grind off the edge! 😀

Let's just say I was super extra careful to make sure nothing was going to stop working -- I was nervous as hell, those cards were not cheap when I got it.

 

[kennyman]

@Lou - No worries, thanks. I`ve been looking for a solution to drive the LG 5K at full 5K resolution with my 6800XT for 3 months now, so far I`ve tried:

Option 1
I have tried to build my own 5K display, gathered info from here and here. However the experience was not great, the colors and resolution are a little bit off when compared to the iMac 5k/LG 5k. I also bought the Realtek controller to control the brightness, contrast etc..., because there is no CMOS battery in the DIY built, the display will not keep/memorize the settings after a shutdown. Sometimes sleep does not work as well, cheap to build thou (under $500).

Option 2
I bought a flashed Thunderbolt 3 Card from here. That also was not stable, it will work but sleep and brightness control will not work with the LG 5K display, and sometimes the screen will turn black.

So the only way to power the LG 5k and use it at full 5K will be to pair it with MPX modules. I found another bidirectional cable with Chrontel CH7213 chipset, the link is here. Is anyone familiar with Delock cables?

 

[Morgonaut]

If someone is interested my in-depth video review of Radeon pro W6800X DUO is out on my YT channel... 🙂

 

[flowrider]

@Lou - No worries, thanks. I`ve been looking for a solution to drive the LG 5K at full 5K resolution with my 6800XT for 3 months now, so far I`ve tried:

Option 1
I have tried to build my own 5K display, gathered info from here and here. However the experience was not great, the colors and resolution are a little bit off when compared to the iMac 5k/LG 5k. I also bought the Realtek controller to control the brightness, contrast etc..., because there is no CMOS battery in the DIY built, the display will not keep/memorize the settings after a shutdown. Sometimes sleep does not work as well, cheap to build thou (under $500).

Option 2
I bought a flashed Thunderbolt 3 Card from here. That also was not stable, it will work but sleep and brightness control will not work with the LG 5K display, and sometimes the screen will turn black.

So the only way to power the LG 5k and use it at full 5K will be to pair it with MPX modules. I found another bidirectional cable with Chrontel CH7213 chipset, the link is here. Is anyone familiar with Delock cables?

There is another option, the cable (link two) that I posted on the previous page:

Belkin Charge and Sync Computer Connection Cable for HUAWEI VR Glass

Adapt HUAWEI VR Glass to connect with computer. Support DisplayPort high-speed transmission. Support HUAWEI VR Glass PC mode 3K 90Hz resolution. 4.5 meters in length, enjoy immersive VR games. 2 USB-A and 1 DisplayPort connet with PC, 1 USB-C port connects with Huawei VR Glass.

www.vmallworld.com

I used that cable for a brief time, and it does activate the Apple Brightness control in Sys. Pref. It MAY also activate 5K. I have not used it that way.

Lou

 

[flowrider]

More from Bare Feats:

Pro W6800X versus other GPUs in Mac Pro 2019

real world speed test results for performance minded Macintosh users

barefeats.com

Lou

 

[goMac]

There is another option, the cable (link two) that I posted on the previous page:

Belkin Charge and Sync Computer Connection Cable for HUAWEI VR Glass

Adapt HUAWEI VR Glass to connect with computer. Support DisplayPort high-speed transmission. Support HUAWEI VR Glass PC mode 3K 90Hz resolution. 4.5 meters in length, enjoy immersive VR games. 2 USB-A and 1 DisplayPort connet with PC, 1 USB-C port connects with Huawei VR Glass.

www.vmallworld.com

I used that cable for a brief time, and it does activate the Apple Brightness control in Sys. Pref. It MAY also activate 5K. I have not used it that way.

Lou

The issue with 5k is that USB-C doesn't have enough bandwidth (without DSC, which the Ultrafine 5k does not support.) Because that cable is a USB-C cable, and not Thunderbolt, it's not likely to support 5k.

I don't think any dual stream DisplayPort -> Thunderbolt solutions exist. If they did, it would probably need to be more than a cable.

 

[avkills]

The issue with 5k is that USB-C doesn't have enough bandwidth (without DSC, which the Ultrafine 5k does not support.) Because that cable is a USB-C cable, and not Thunderbolt, it's not likely to support 5k.

I don't think any dual stream DisplayPort -> Thunderbolt solutions exist. If they did, it would probably need to be more than a cable.

Actually OWC does make a Thunderbolt 3 > Dual DP adapter, but I am not sure it will work in the opposite direction. But I do know it is capable of doing 2x 3840x2160 @ 59.94Hz outputs; and I have hooked 2 adapters to 1 iMacPro before and had 4x 4k outputs at 59.94hz; being driven by Millumin.

OWC Thunderbolt Interface Adapters

Find the best interface adapter for your Thunderbolt workflow. Connect multiple high-resolution displays, add 10G Ethernet, and much more.

www.owcdigital.com

 

[bsbeamer]

Actually OWC does make a Thunderbolt 3 > Dual DP adapter, but I am not sure it will work in the opposite direction. But I do know it is capable of doing 2x 3840x2160 @ 59.94Hz outputs; and I have hooked 2 adapters to 1 iMacPro before and had 4x 4k outputs at 59.94hz; being driven by Millumin.

OWC Thunderbolt Interface Adapters

Find the best interface adapter for your Thunderbolt workflow. Connect multiple high-resolution displays, add 10G Ethernet, and much more.

www.owcdigital.com

Customer Service

Upgrade the RAM and storage of nearly any Apple computer at MacSales.com. We also provide refurbished Macs, external storage, docks, accessories, and more!

eshop.macsales.com

I’d suggest someone contact their support if you’re willing to pay their prices.

 

[joevt]

There is another option, the cable (link two) that I posted on the previous page:

Belkin Charge and Sync Computer Connection Cable for HUAWEI VR Glass

Adapt HUAWEI VR Glass to connect with computer. Support DisplayPort high-speed transmission. Support HUAWEI VR Glass PC mode 3K 90Hz resolution. 4.5 meters in length, enjoy immersive VR games. 2 USB-A and 1 DisplayPort connet with PC, 1 USB-C port connects with Huawei VR Glass.

www.vmallworld.com

I used that cable for a brief time, and it does activate the Apple Brightness control in Sys. Pref. It MAY also activate 5K. I have not used it that way.

Can't do LG UltraFine 5K at 5K with a single DisplayPort connection unless you try 5K 39Hz.

The issue with 5k is that USB-C doesn't have enough bandwidth (without DSC, which the Ultrafine 5k does not support.) Because that cable is a USB-C cable, and not Thunderbolt, it's not likely to support 5k.

USB-C DisplayPort Alt Mode has plenty of bandwidth for 5K but it's mostly modes you don't want to use (39Hz) or modes that are not supported by the LG UltraFine 5K.
HBR2: 45Hz 8bpc, 37Hz 10bpc (but 39Hz is the max the LG UltraFine 5K will accept)
HBR3: 68Hz 8bpc, 55Hz 10bpc (but the LG UltraFine 5K does not accept HBR3)
HBR2 + DSC: 90Hz (but the LG UltraFine 5K does not support DSC)
HBR3 + DSC: 133Hz (but the LG UltraFine 5K does not support DSC)
(the LG UltraFine 5K does not support 4:2:2 or 4:2:0; macOS does not support 6bpc - not sure if the LG UltraFine supports 6bpc)

For 60Hz 10bpc RGB, the LG UltraFine 5K requires two HBR2 x4 DisplayPort connections over Thunderbolt.

I don't think any dual stream DisplayPort -> Thunderbolt solutions exist. If they did, it would probably need to be more than a cable.

They exist as Thunderbolt 3 or Thunderbolt 4 add-in cards. Getting them to work with an LG UltraFine 5K should be easy except for the display's weird requirements for powering itself on (it has no buttons). Plus you need the PCIe functionality to get to the USB controller of the display to use the USB functions of the display (brightness control, camera, audio, etc.)

Actually OWC does make a Thunderbolt 3 > Dual DP adapter, but I am not sure it will work in the opposite direction. But I do know it is capable of doing 2x 3840x2160 @ 59.94Hz outputs; and I have hooked 2 adapters to 1 iMacPro before and had 4x 4k outputs at 59.94hz; being driven by Millumin.

OWC Thunderbolt Interface Adapters

Find the best interface adapter for your Thunderbolt workflow. Connect multiple high-resolution displays, add 10G Ethernet, and much more.

www.owcdigital.com

A Thunderbolt 3 to Dual DisplayPort adapter is just a cut-down bus-powered Thunderbolt dock. You can't do DisplayPort input to a Thunderbolt dock so you can't do DisplayPort input to this adapter. Thunderbolt docks do not expose the DisplayPort inputs of their Thunderbolt controller. Only the Blackmagic eGPUs and Sonnet eGPU Puck 5500 XT / 5700 have ever used the DisplayPort inputs of a Thunderbolt controller (outside the Thunderbolt controllers of Macs).

 

[flowrider]

Can't do LG UltraFine 5K at 5K with a single DisplayPort connection unless you try 5K 39Hz.

Is that still true if the stock Pro580X is left installed and the two USB pigtails from the Belkin cable are plugged into the NcMP?

Lou

 

[goMac]

Is that still true if the stock Pro580X is left installed and the two USB pigtails from the Belkin cable are plugged into the NcMP?

Lou

The USB pigtails, AFAIK, would not carry DisplayPort data so having them plugged or unplugged would not make a difference for resolution. A 5,1 (or any computer) can't route a DisplayPort signal over a USB-A port. Especially from a PCI-E GPU that has no link back to the USB system.

 

[flowrider]

^^^^But, the 7,1 does carry a video signal through the USB ports when an MPX module is installed.

However, I ado realize all this is academic until someone tries it.

Lou

 

[goMac]

^^^^But, the 7,1 does carry a video signal through the USB ports when an MPX module is installed.

However, I ado realize all this is academic until someone tries it.

Lou

Not through USB-A. Only USB-C is capable of transporting a video signal. The USB-A protocols don't support it. I don't think even an adapter can coax USB-A to carry a DisplayPort signal.

(Now waiting for someone to post some poor DisplayPort cable that's been spliced directly into a USB-A cable.)

 

[joevt]

Is that still true if the stock Pro580X is left installed and the two USB pigtails from the Belkin cable are plugged into the NcMP?

The USB pigtails of the Belkin cable are for power and USB 2.0 for the USB-C DisplayPort Alt Mode display connection at the LG UltraFine 5K end. The Belkin cable has only one DisplayPort connection, so it can only transmit one DisplayPort signal to the LG UltraFine 5K.

The LG UltraFine 5K display can only accept two DisplayPort signals from Thunderbolt.

Now, another method to send two DisplayPort streams over a DisplayPort connection is to use MST. Apple supports this for old 4K displays but not 5K displays like the Dell UP2715K or (LG UltraFine 5K with Thunderbolt conversion) because in the 5K case, the two streams need to be converted to two separate SST outputs (macOS doesn't support MST for multiple SST outputs).

 

[flowrider]

Well, I did something sorta stupid I just replaced my Reference RX6800 with a Gigabyte RX6800XT

Checked Metal scores:

My RX6800


My RX6800XT


RX6900XT (from another post)



BTW - My Reference RX6800 is now for sale. Check the MarketPlace if interested.

Lou

 

[DFP1989]

Pretty decent bump between non-XT and XT, lacklustre boost for the 6900XT considering the significant price premium.

 

[flowrider]

Just to add something that surprised me. While changing the cards, I was holding both at the same time, and somewhat befuddled to feel that the Reference card was much heavier than the Gigabyte card. Even though the Gigabyte is bigger in every dimension and has the backplate that the Reference lacks😱

Lou

 

[Grumply]

Just to add something that surprised me. While changing the cards, I was holding both at the same time, and somewhat befuddled to feel that the Reference card was much heavier than the Gigabyte card. Even though the Gigabyte is bigger in every dimension and has the backplate that the Reference lacks😱

Lou

I was a little worried about the cards being too heavy, but the Gigabyte's are a reasonable weight - if only they'd made them a reasonable HEIGHT as well - I wouldn't be losing THREE PCI ports to them.

The extra weight on the reference card will just be down to them using a little more metal in the heatsinks.

 

[fedism]

I put an AMD RX6900XT Reference Model into a customer 5.1 machine.

it even wont post (no chime).

I added an uga GPU and it got to a Firmware loop (loud chime, chime, chime, chime....) in one second rhythm.

I asume a glitch in the RX Bios with Mac Firmware.

Mac Firmware was 144, rebuilt with latest bootloader.

GPU was new in a sealed box.

have no PC to double check the GPU but doubt it is defective.

Mac and GPU is back to the customer.

Did PSU mod for powering the GPU. But also doubt it is current related.


this model
View attachment 1752575

It looks like at this time big sur didnt support amd 6000 cards but now they do. Do you remember what big sur version it was?

 

[Macschrauber]

none, the machine has not started. This is firmware related.

 

[fedism]

none, the machine has not started. This is firmware related.

Just to be clear, you did try big sur 11.4 and after?
I hope not because you will kill my dreams of running big navi on my 5,1

 

[goMac]

Just to be clear, you did try big sur 11.4 and after?
I hope not because you will kill my dreams of running big navi on my 5,1

Windows won't work with Big Navi on a 5,1 either. Like Macschrauber said, it's a firmware incompatibility. And Big Sur doesn't include 5,1 updates.

So.... dreams crushed so far. Big Navi does not work on 5,1.

 

[fedism]

Windows won't work with Big Navi on a 5,1 either. Like Macschrauber said, it's a firmware incompatibility. And Big Sur doesn't include 5,1 updates.

So.... dreams crushed so far. Big Navi does not work on 5,1.

I have been gathering hours upon hours of information to the tent Big Sur 11.5 specifically for this reason, at least I know I am in no rush to do so because I sincerely just wanted a graphics card update, I even use windows on my cMP 5,1 with a Vega 56 flashed for Mac OS, so you mentioning that was helpful to me.

 

[Macschrauber]

I dont vote that all Big Navis dont work in a Mac Pro 5.1 - but this particular model I tested don't let the Mac Pro 5.1 Firmware finish starting.

Maybe others work, maybe other firmwares work.

I had no possibilities to fiddle with the firmware as it was a brand new customer card and I had limited time avail.

 

[goMac]

I dont vote that all Big Navis dont work in a Mac Pro 5.1 - but this particular model I tested don't let the Mac Pro 5.1 Firmware finish starting.

Maybe others work, maybe other firmwares work.

I had no possibilities to fiddle with the firmware as it was a brand new customer card and I had limited time avail.

From what I've seen, there are multiple reports of Big Navi not working on 5,1s, and no reports of it working. If there is a config working, no one has reported it yet.

And because Apple is no longer producing firmware updates, no versions of Big Sur (or Monterey) are going to fix.