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Dual RX 480s in Mac Pro 5,1 running MacOS (w/ How-to)

rdej47 said:
Hey guys I stumbled upon this thread after I decided to purchase a MSI RX 480 (https://ca.msi.com/Graphics-card/Radeon-RX-480-ARMOR-4G-OC.html#hero-overview). Obviously I didn't do enough research and failed to realize that this particular card has an 8-pin slot and not the 6-pin.

Now I know there are 8-pin to 6-pin adapters (and even 8-pin to dual 6-pin), what i'm wondering is if a dual adapter is necessary. Looking at the power consumption it's 150W. If I buy a single 8-pin to 6-pin adapter, that would give me 75W with the remaining 75W coming from the PCI-E slot.

Is this accurate? Anything else I should consider. Definitely new to GPU's since this is the first real desktop tower I've had in a long time.
Click to expand...

No, 75W from slot and 75W from the 8pin is just what you want, not necessary what will happen.

It can be 0W from slot and 150W from the 8pin.

How you drive the 8pin won't change the power draw distribution (that's controlled by the firmware).

Anyway, I suggest you buy a dual mini 6pin -> 8pin cable. That will safely power your card.
 
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h9826790 said:
No, 75W from slot and 75W from the 8pin is just what you want, not necessary what will happen.

It can be 0W from slot and 150W from the 8pin.

How you drive the 8pin won't change the power draw distribution (that's controlled by the firmware).

Anyway, I suggest you buy a dual mini 6pin -> 8pin cable. That will safely power your card.
Click to expand...

I was looking at some at Amazon, wondering how they work and if there's any issues I'd have with this. What's weird is that the RX 480 from the initial post has the 6 pin.
 
Fl0r!an said:
Btw, I'd have expected native Polaris 10 support in the near future, as the iMacs are due for an update. Not sure how to interpret the removal of AMD9500Controller, I guess it doesn't mean a lot, might come back with a new name when the iMacs arrive.
Click to expand...

Perhaps :apple: removed for testing macOS w/out it,
before adding Polaris 10 support for the new Macs in another dot4 beta.

Worst case scenario and perhaps better for us: Vega 11 added instead of Polaris 10

Although, the new Mac is strongly suggested as an "early 2017" model - too early for Vega 11

I suspect :apple: will add Polaris 10 support, and the recent kext changes are in preparation for it.
 
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Daniel Reed said:
Thanks for the quick update.
So, its safe still for 10.12.3 ?
Click to expand...
Daniel Reed said:
Perhaps :apple: removed for testing macOS w/out it,
before adding Polaris 10 support for the new Macs in another dot4 beta.

Worst case scenario and perhaps better for us: Vega 11 added instead of Polaris 10

Although, the new Mac is strongly suggested as an "early 2017" model - too early for Vega 11

I suspect :apple: will add Polaris 10 support, and the recent kext changes are in preparation for it.
Click to expand...
Which recent kext changes are these?
 
rdej47 said:
I was looking at some at Amazon, wondering how they work and if there's any issues I'd have with this. What's weird is that the RX 480 from the initial post has the 6 pin.
Click to expand...

My guess would be either the RX480 come with factory OC, therefore will demand a bit more power.

Or they want to reduce the power draw from the slot (the 1st batch of RX480 can draw more than 75W for the slot. And it kill some computer).

Or just leave some room for the user to OC the card.
 
So I decided to see what would happen and put the 480 in with a 8-pin to 6-pin. Seems to be running fine and the fan's don't in until it's put under some load.

I've been trying to track down a 8 pin to dual 6-pin but so far i've only been able to find things on ebay in China. Has anyone ordered one of these cables from there and had a good/bad experience?
 
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I'd strongly suggest to observe the power draw on PCIe slot and booster. You might be fine, but it's better to doublecheck.
 
Hi,

I've just received my RX480. Successfully make it work in my MacPro5.1(4.1). But I discover that perhaps in the next public update 10.2.4, it will no more be possible to use it :( . I'm almost ready to get back the RX480 to my reseller...

Which PC card to use in my Mac ??? A good one as good as the RX480 ??? In the same price range ???

Pffff... Apple... :(
 
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Vinc26 said:
Hi,

I've just received my RX480. Successfully make it work in my MacPro5.1(4.1). But I discover that perhaps in the next public update 10.2.4, it will no more be possible to use it :( . I'm almost ready to get back the RX480 to my reseller...

Which PC card to use in my Mac ??? A good one as good as the RX480 ??? In the same price range ???
Click to expand...

RX 460 should continue to work and is cheaper.
Should continue working as its Polaris 11 used in 2016 MBP.
Could even get and install two RX 460 for the price of one RX480.
https://www.amazon.com/STRIX-Radeon-Gaming-Graphics-STRIX-RX460-O4G-GAMING/dp/B01K1JVQI4/
https://www.amazon.com/Gigabyte-Radeon-Windforce-Graphics-GV-RX460WF2OC-4GD/dp/B01K1JVCRE/

OR

Get a GTX 970 4GB for $200 USD
It's performance is similar to RX 480 and Nvidia provides drivers.
http://www.evga.com/products/produc...ily=GeForce+900+Series+Family&chipset=GTX+970

Later in the year Vega 11 and/or Vega 10 may be supported based on 2017 Mac releases.
 
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rdej47 said:
I've been trying to track down a 8 pin to dual 6-pin but so far i've only been able to find things on ebay in China. Has anyone ordered one of these cables from there and had a good/bad experience?
Click to expand...

Yah I have the same question too. I'm planning to try out some aftermarket RX 480s (8GB) as not many cMP users have mentioned about them much on account of review, benchmark, etc. I am not sure why. Could somebody share your experience with dual (2x) mini 6-pins to 8-pins power cables? Such cables are barely or not at all available in US market. If any of you is familiar with the cable, could you plz help us verify it if it sure is compatible with cMP? It'd be much appreciated.

Update: On Amazon, what is available for the best option is:
Dual (2x) Mini 6 pin to 8 pin PCIe Power Adapter Cable by LHT | 18AWG (Male-Male) Connector for Graphic Video Card Upgrade in All Mac Pro

After 6 month of usage, it has proven well worth it! Without any hiccups, according to my test data it can deliver the sufficient power demand of RX 480, RX 580, GTX 980 and GTX 1070 for gaming with ultra settings on Resident Evil 7 and Battle Field 4.
 
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Fl0r!an said:
I'd strongly suggest to observe the power draw on PCIe slot and booster. You might be fine, but it's better to doublecheck.
Click to expand...


Thanks! I downloaded iStat and I've got the power draw loaded up in the menu bar. For basic tasks the PCIe slot and the PCIe boost/aux hover around .5A - 2A. When I start working in Motion it starts averaging around 2A - 4A. Does that sound normal or what kind of numbers should I be looking at?
 
Sounds perfectly fine, not even 50W. Compute applications are usually not that demanding though, the power draw will surely increase when running games. Running FurMark should give you an idea what the worst case power draw looks like.
 
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Daniel Reed said:
RX 460 should continue to work and is cheaper.
Should continue working as its Polaris 11 used in 2016 MBP.
Could even get and install two RX 460 for the price of one RX480.
..
Click to expand...
Is this really necessary, apart from that the RX460 is officially supported?
As I understand it, the RX480 will work on 10.12.4 as on 10.12.3, if we put the PCI ID on both kexts.
Or am I missing something?
 
JoSch said:
Is this really necessary, apart from that the RX460 is officially supported?
As I understand it, the RX480 will work on 10.12.4 as on 10.12.3, if we put the PCI ID on both kexts.
Or am I missing something?
Click to expand...
I think you have it right. It doesn't bode well for the direction Apple is heading though.
 
H2SO4 said:
I think you have it right. It doesn't bode well for the direction Apple is heading though.
Click to expand...
Well, I disagree. They certainly don't want to support at the moment. They just adjusted their kext to reflect that.
It doesn't mean, that there will never be support for the Polaris 10 GPUs. Why shouldn't they? It's a cheap, not too power consuming, yet powerful GPU. It works great with FCPX. That's exactly what Apple wants and needs.
 
Daniel Reed said:
RX 460 should continue to work and is cheaper.
Should continue working as its Polaris 11 used in 2016 MBP.
Could even get and install two RX 460 for the price of one RX480.
https://www.amazon.com/STRIX-Radeon-Gaming-Graphics-STRIX-RX460-O4G-GAMING/dp/B01K1JVQI4/
https://www.amazon.com/Gigabyte-Radeon-Windforce-Graphics-GV-RX460WF2OC-4GD/dp/B01K1JVCRE/

OR

Get a GTX 970 4GB for $200 USD
It's performance is similar to RX 480 and Nvidia provides drivers.
http://www.evga.com/products/produc...ily=GeForce+900+Series+Family&chipset=GTX+970

Later in the year Vega 11 and/or Vega 10 may be supported based on 2017 Mac releases.
Click to expand...

And for using with FCPX : 2x RX460 or one GTX 970 ? :confused:
 
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JoSch said:
As I understand it, the RX480 will work on 10.12.4 as on 10.12.3, if we put the PCI ID on both kexts.
Or am I missing something?
Click to expand...

It will work after adding the device ID blindly (-> VNC, 2nd GPU, ...) after each OS update.

I guess it's a better idea to stay on 10.2.3 and wait for an OS update which introduces native Polaris 10 support.
 
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