Please Help w/ Video Card Power Connection/AMD Radeon Pro WX 9100 work in cMP 5,1?

ZombiePhysicist

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Has anyone gotten the 9100 to work in your 5,1 cMP? Apple says this card is supported for Mojave.

When I plugged it in using this cable:
https://www.amazon.com/gp/product/B00M49SELW/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
It screamed like a banshee.

I have since ordered this and will cross my fingertips praying it makes a difference:
https://www.amazon.com/gp/product/B07HLP4647/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
But I suspect the problem not enough power.

Has anyone gotten this card to work, and if so, what power cabling did you use? I suspect if I put in another power supply that would be enough? Thanks for any pointers!

For what it's worth, here are the plugs the card has.
 

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ZombiePhysicist

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I searched for "Mac Pro 2 X Mini 6 pin to 1 8 pin plus two SATA to one 6 pin" and it only came back to this thread. :(

The link to netkas was just to the general site. Searching for the string didn't bring up anything that I could understand as relevant (e.g., Mac Mini Firmware Upgrade Utility Needed).

Thankfully my Mac Pro is fine (at least when I put in the original video cards). Would appreciate any points in how to properly connect the power lines. Sorry, I dont understand what you mean by clipping SATA power cables as I'm not using SATA.

Sorry if I'm oblivious. I feel like I thought I was just getting in a shallow pool to hook up a power lead in a tower and may have wandered into the Marianas Trench.
 

MIKX

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The sockets that power your internal hard drives have two parts. . (1) power (2 ) data transfer.

You can use the POWER part of the socket by using the cable in the photo below . . .but the cable has a tab on either side . .one of them needs to be clipped off to allow the cable to be inserted correctly because the DATA transfer part of the on board socket gets in the way.



This cable to connect from the Mac Pro's 6 pin to 8 pin socket
https://www.ebay.com/itm/18AWG-Dual-Mini-6-Pin-Male-To-8-Pin-PCI-e-Y-Splitter-Power-Cable-For-Mac-Pro/273406546488?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649


This cable for the 6 pin socket https://asset.conrad.com/media10/is...pg?x=1000&y=1000&ex=1000&ey=1000&align=center

2 x SATA to 1 x 6 pin.jpg


You plug these into your internal SATA HDD sockets but you'll have to clip off one of the side tabs to be able to insert it. Shut down your Mac Pro, unplug the power cord, lay the Mac Pro on it' side .. now work out which of the SATA tabs you have to clip off. If you can't work that out you need your eyes tested. :D

Use a piece of string to measure how long the cable needs to be to reach the GPU's 6 pin socket when ordering.

AliExpress is a good place to buy cables but longish delivery times.
https://www.aliexpress.com/item/Fre...6-Pin-Female-Video-Card-Power/2041017613.html

Using this cable you will lose two hard drives spaces. Or if you can get a really long one. . you could remove your DVD drive and use the two SATA cable there. . have a look . .you'll see what I mean.
 
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ZombiePhysicist

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So thanks very much MIKX. That got the video card to come up and work! Now the problem is I cannot close the case as I have the wires dangling down the side of the case to get to the card, and the cables are too thick for the case to close.

I guess I would have to take apart the entire machine and re-route those sata power cables to the motherboard? That sounds like a painful procedure. :(

But thank you so much for the help!
 

ZombiePhysicist

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It was wired towards the outside of the case. Here are some pics. You can see in the 4th image where the card is seated in the slot, I'm draping the SATA power cables over and through the 2nd drive bay.
 

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MIKX

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You can move two of your internal hard drives you can use the SATA sockets above your GPU.
You can put those two hard drives into the DVD drive space. I think the mounting holes allow for them to be connected to where normally two DVD drives are connected.
 
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ZombiePhysicist

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You can move two of your internal hard drives you can use the SATA sockets above your GPU.
You can put those two hard drives into the DVD drive space. I think the mounting holes allow for them to be connected to where normally two DVD drives are connected.
Oh, that is a super great idea. So straight off the motherboard there. I think that should work. A bit extreme, on the other hand, since I just dont need the spinners, that's a nice solution to get me by until the new Mac Pro is released (fingers crossed it's not some un-upgradable disaster like the iMac Pro/MacBook Pro)...

Thanks so much MIKX!
 

MIKX

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Congratulations ! That's a very powerful & expensive GPU.
Make sure that the GPU SATA to 6 pin cables are firmly inserted on the motherboard and also to the GPU 6 pin socket. Check . . and then . . check again.
 
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Pressure

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As far as I am aware all graphic cards with DisplayPort (1.2+) support Multi-Stream Transport (MST) so you can daisy chain 2 monitors, no? Or buy a dock with MST. A single DP1.4 can drive 8 x 1080p monitors.
 

ZombiePhysicist

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As far as I am aware all graphic cards with DisplayPort (1.2+) support Multi-Stream Transport (MST) so you can daisy chain 2 monitors, no? Or buy a dock with MST. A single DP1.4 can drive 8 x 1080p monitors.
Maybe the mst works better now but every time I tried it failed. Paps is because my monitors are 2560x1600, but the mst dongles I got never worked.
 

ZombiePhysicist

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The Apple 30" displays are DVI dual link and have a DVI dual link to mini display port adapter. That adapter has always been a "barely working" solution.
 

Ludacrisvp

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MST for multiple displays is not supported in MacOS, it only works for a single display or for mirroring.
 
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