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

S

sebh

macrumors member
Jan 9, 2015
44
3
munich
s4ru said:
No. I don’t have an access for Big Sur beta build.


BTW, after a bit of a hassle, Bootcamp Win 10 recognized the 6900XT.
Followed Apple procedure, I needed to uninstall the driver for MPX and remove the module itself, and finally Win 10 recognized the card. I’m not familiar with PCs, so it took me a lot of time to figure it out.
Click to expand...
I had the same Problem with my Mac Pro and 6900XT. i had to boot up with MPX and 6900XT.Remove the driver for W5700X and shut down. Install the 6900XT driver trough device manager. Shut down and remove the MPX boot up with no boot screen and install the AMD driver with setup. Shut down again and now i boot up with MPX and 6900XT and install the driver (BootcampDrivers.com) for my W5700X Pro with device manager. Now i have both in Windows and 6900XT as primary.

Time Spy Score:16775
Fire Strike Extreme Score:22985
with Mac Pro 16Core
 
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iPhoNewsRO

iPhoNewsRO

macrumors newbie
May 6, 2016
8
9
ok so i installed a 6900xt in a hackintosh build where i had a 5700xt before. there is no hardware acceleration aka i got display output but everything is slow, no transparencies and no custom resolutions.

its usable but not a good user experience. we need native support
 
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S

s4ru

macrumors newbie
Feb 10, 2020
17
27
Patiently waiting for a driver…

MacPro_dual6900XT_01.png
MacPro_dual6900XT_02.png
 
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flowrider

flowrider

macrumors 604
Nov 23, 2012
7,230
2,957
Gigabyte's card announced. It's huge. Three 8 pin connectors. 850 watt PS requirement. 16GB of GDDR6. $1200 price tag. An Aorus version coming later.

TinyGrab Screen Shot 12-31-20, 10.33.32 AM.png
TinyGrab Screen Shot 12-31-20, 10.34.34 AM.png

Lou
 
H

hifimac

macrumors member
Mar 28, 2013
61
40
So this definitely won't work in a Razor Core X eGPU with stock PSU? What about a reference model?
 
brandon_macpro

brandon_macpro

macrumors newbie
Dec 31, 2020
27
3

s4ru i have the same mac pro setup. are those 2 6800xt or 2 6900xt. looking to add that same setup when I can find them in stock. I only thought I could fit one.​

 
DFP1989

DFP1989

macrumors 6502
Jun 5, 2020
462
362
Melbourne, Australia
flowrider said:
Gigabyte's card announced. It's huge. Three 8 pin connectors. 850 watt PS requirement. 16GB of GDDR6. $1200 price tag. An Aorus version coming later.

View attachment 1704314
View attachment 1704315

Lou
Click to expand...
The reference card looks so much better than that.

Side note, it’s a shame the reference card doesn’t let you flip the logo up the other way for systems with cards mounted the opposite way to normal (like Mac Pro).
 
flowrider

flowrider

macrumors 604
Nov 23, 2012
7,230
2,957
^^^^The Gigabyte logo would be upside down too?

I have an Aorus RX5700XT in my NcMP, and the lighted logo is upside down in that. I never gave it much attention?

Lou
 
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DFP1989

DFP1989

macrumors 6502
Jun 5, 2020
462
362
Melbourne, Australia
flowrider said:
^^^^The Gigabyte logo would be upside down too?

I have an Aorus RX5700XT in my NcMP, and the lighted logo is upside down in that. I never gave it much attention?

Lou
Click to expand...
Obviously doesn’t matter in our systems, but just would be kinda nice ?

Has anyone been able to find details on the decode/encode support for these cards yet? I search and search, but can’t find an answer to whether HEVC 10-but 4:2:2 hardware decode is supported. It’s literally the only reason I want one of these cards.

Still super annoying that my M1 Mac can play footage off my R5/1DX smoothly while my 16-core W5700X equiped Mac Pro stutters moments after the play head starts moving.
 
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S

s4ru

macrumors newbie
Feb 10, 2020
17
27
brandon_macpro said:

s4ru i have the same mac pro setup. are those 2 6800xt or 2 6900xt. looking to add that same setup when I can find them in stock. I only thought I could fit one.​

Click to expand...

Yes. They are two 6900 XTs. I used a short PCI riser cable for one of the card to manage the installation of the dual 6900 XT.


The setup pictured previously had a PCI lane allocation issue though. In the OS’s Expansion Slot Utility, Pool A Allocation was 100%, whereas Pool B had 125%. That is because I had an OWC Accelsior 4M2 (x8 card) in Slot 3, which is x16.

Searching for a web, I found a very useful article about the MacPro’s PCI lane allocation.
softron.zendesk.com

HOW TO: Install PCIe cards in your 2019 Mac Pro

The 2019 Mac Pro allows to connect PCIe cards. Apple gives some recommendations on how to install and configure them. But below are some more recommendations. How to open the "Expansion Slot...
softron.zendesk.com softron.zendesk.com



After reading it, I re-did the cards installation.
Here’s the config;

Slot 3 (x16) is populated with the first 6900XT.
Slot 4 (x16) is obscured by the card so it is not accessible.
Slot 5 (x16) is filled with a riser cable so that the second 6900 XT can be used in offset way, in between Slot 4 and 5, making some head room.
Slot 6 (x8) is obscured by the card.
Slot 7 (x8) is populated with OWC Accelsior 4M2.
Slot 8 (x4) is populated with Mac Pro I/O card.


The PCI bracket of the second 6900 XT is removed because the card is slightly protruded due to riser cable. The card is not secured in anyway. It just sits on the first card with sponge spacer in between. This is the reason I chose the first setup attempt, in which a 6900 XT sat more firmly and somehow was sticked to the Accelsior with a thermal silicone pad in between them.

Anyway, the PCI lane allocation seems better now.

Pool A Allocation is 100% and Pool B is 75%, reserving some spare resources for Thunderbolt devices. Actually, with eGPU attached, Pool B goes to 100%.


Hope Big Sur will natively support the card soon.

MacPro_dual6900XT_03.png
MacPro_dual6900XT_04.png
MacPro_dual6900XT_05.png
MacPro_dual6900XT_06.png
MacPro_dual6900XT_07.png
 
DFP1989

DFP1989

macrumors 6502
Jun 5, 2020
462
362
Melbourne, Australia
Would you keep the Vega in there once the RX6900s are supported though?

I get that giving up the Thunderbolt ports is a major downside to taking it out.
 
brandon_macpro

brandon_macpro

macrumors newbie
Dec 31, 2020
27
3
s4ru thank you for sharing a breakdown of the build. Really helps me moving forward in purchasing 2 6900xts soon. For the cables. Did you just use the ones on the apple website that they sell for mac pro? If not can you provide a link? Can you share a link on where to purchase the GPU Riser? In order to fit the same configuration as shown.
 
S

s4ru

macrumors newbie
Feb 10, 2020
17
27
The power cables are from Belkin that Apple sells.

Belkin AUX Power Cable Kit for Mac Pro - Apple

Apple Store Search Results
www.apple.com
Click to expand...


The GPU riser cable I used is this. 5cm 90 Degree angled one.
https://www.amazon.com/LINKUP-Shielded-High-Speed-2020┃Universal-Compatible/dp/B08P3S8TPT/ref=sr_1_3?crid=23BXC80LLUWS9&dchild=1&keywords=linkup%2Bpcie%2B4.0&qid=1609723868&sprefix=LINKUP%2B%2Caps%2C327&sr=8-3&th=1
Click to expand...


I also ordered ADT-LINK riser cable too but haven’t received yet.
I guess this one fits better because it’s got smaller print board than LINKUP.
www.amazon.com

ADT-LINK PCI-E X16 to 16X 3.0 Male to Female Riser Extension Cable Graphics Card Computer Chassis PCI Express Extender Ribbon 128G/Bps (R33SL 5CM)

Specifications: Product name: PCIe graphics card extension cord Product model: R33SL Vertical Angle / R33SF Flat / R33SR Reverse Connector 1:? PCIe x16 male Connector 2:? PCIe x16 female Left Angled Wire length: 5 ~ 100 cm, the length can be customized, welcome to contact our Customer service. Co...
www.amazon.com
Click to expand...

Both brand has left-angled riser which seems better fit but a ribbon cable might be too long for this purpose.



I think 6900 XT reference model has got perfect size for dual installation in Mac Pro. Other OC models might have thicker and longer size so it could be more difficult to fit in.

*Edited. Seems Amazon URL does not work properly so I quoted the links.
 
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