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

[wickerstick]

Ok and back. happy to report the 1338 Mhz XFX RX 480 works no problem so far in OSX and Windows! here are some pics. I will be running benchmarks later this week when i install my x5690's. (still waiting on 5mm thermal pad to get here). I think I will keep the single RX480 until something better comes along as I prefer a single card to crossfire setups for most instances.

 

[kalisz]

Ok and back. happy to report the 1338 Mhz XFX RX 480 works no problem so far in OSX and Windows! here are some pics. I will be running benchmarks later this week when i install my x5690's. (still waiting on 5mm thermal pad to get here). I think I will keep the single RX480 until something better comes along as I prefer a single card to crossfire setups for most instances.

If you want to max out your Mac Pro configuration don't forget to change memory to 1333MHz in triple channel

 

[theitsage]

Ok and back. happy to report the 1338 Mhz XFX RX 480 works no problem so far in OSX and Windows! here are some pics. I will be running benchmarks later this week when i install my x5690's. (still waiting on 5mm thermal pad to get here). I think I will keep the single RX480 until something better comes along as I prefer a single card to crossfire setups for most instances.

How's text scaling on your Samsung 28" 4K monitor? I have an LG 27" 4K and scaling doesn't work in Sierra. The About This Mac > Display may show 3840 x 2160 but the monitor is possibly running at 1920 x 1080. Look in Display/Graphics within System Profiler to confirm.

 

[AndreeOnline]

I tied to install a flexible PCIe cable today to allow me to have two double width gfx cards, as well as my USB3 card and my SSUBX SSD.

Unfortunately it won't work. It's very close, but ultimately the slot 2 gfx card can't be seated properly.

I've reverted back to MSI RX 480 8GB + MSI 280X 3GB and my SSUBX SSD. At this point I don't have USB 3.

I think I'll have to sell my 280X and drop another RX 480 in there to run identical cards for FCPX to give me 2x performance. Also, I don't think I'm getting the full 8GB usage in Resolve when I run this mismatch of cards, even if Resolve uses both cards fully for compute.

While the RX 480 actually is a wee bit weaker than my 280X currently, it's so little between them that I think it's more of a benchmark thing and not important in real life. It'll be satisfying to have two identical 8GB cards in there that are fairly power efficient. With some luck we'll even get better drivers soon.

 

[theitsage]

That's too bad to hear @AndreeOnline. Was it because of the cooler on the GPU? I'd hang on to the R9 280x until boot screen on Polaris cards is a possibility.

I'm done trying to make my Mac Pro into a gaming machine. Got an Alienware Area 51 this weekend and that thing handles 3-way Crossfire with ease.

 

[Pandanl]

Ok and back. happy to report the 1338 Mhz XFX RX 480 works no problem so far in OSX and Windows! here are some pics. I will be running benchmarks later this week when i install my x5690's. (still waiting on 5mm thermal pad to get here). I think I will keep the single RX480 until something better comes along as I prefer a single card to crossfire setups for most instances.

Good to hear, did you get a good deal on those X5690's. Ebay prices are very high and twice the price of a X5680.

I'm still waiting for 2 X5680 and a mini pcie 6 to 8 pin pcie cable to get my RX 480 Nitro 4GB working.

 

[killawat]

I'm done trying to make my Mac Pro into a gaming machine. Got an Alienware Area 51 this weekend and that thing handles 3-way Crossfire with ease.

Very cool. I've got an AW 15 on the way with 1070 GPU, very exciting when compared to my 2010 330M that couldn't even play anything when it was first released haha.

 

[Synchro3]

I tied to install a flexible PCIe cable today to allow me to have two double width gfx cards, as well as my USB3 card and my SSUBX SSD.

Unfortunately it won't work. It's very close, but ultimately the slot 2 gfx card can't be seated properly.

Maybe a pci express extender cable with 90 degree angle could work.

How's text scaling on your Samsung 28" 4K monitor? I have an LG 27" 4K and scaling doesn't work in Sierra. The About This Mac > Display may show 3840 x 2160 but the monitor is possibly running at 1920 x 1080. Look in Display/Graphics within System Profiler to confirm.

For more resolutions hold Option down when you click "Scaled" and more resolutions show up.

The 'normal' resolutions are already HiDPI, the others are defined '(low resolution)'.

 

[AndreeOnline]

Maybe a pci express extender cable with 90 degree angle could work.

With the one I have, I can fold the cable really flat directly out of the connector itself. It's very low profile. I'm not ruling out that there might be ones even lower, but I don't think I'll try another at this point.

Even if the cable gets routed to the side instead of upwards, there needs to be a clamp somehow. I'm don't see that it can be made much smaller. If you care to google and post pictures I can guesstimate if it'll fit.
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That's too bad to hear @AndreeOnline. Was it because of the cooler on the GPU? I'd hang on to the R9 280x until boot screen on Polaris cards is a possibility

I have an Apple original Nvidia 120 card laying around as fallback. But as long as the RX 480 boots to allow for .kext editing I'm good.

My 280X isn't flashed, so it adds no additional functionality.

 

[SoyCapitanSoyCapitan]

Much faster than a 280X if supported by an operating system with good APIs and drivers.

 

[wickerstick]

If you want to max out your Mac Pro configuration don't forget to change memory to 1333MHz in triple channel

The memory will run at 1333 once the processors are swapped

How's text scaling on your Samsung 28" 4K monitor? I have an LG 27" 4K and scaling doesn't work in Sierra. The About This Mac > Display may show 3840 x 2160 but the monitor is possibly running at 1920 x 1080. Look in Display/Graphics within System Profiler to confirm.

by default in os sierra at least for me it scales at 1920, however if you look at the other resolutions scaling works well. I dialed mine in at 3008 currently, my display is a Samsung uhd so not true 4K. I'll be upgrading it down the line though. I search google for the iMac 4K scaling options

Good to hear, did you get a good deal on those X5690's. Ebay prices are very high and twice the price of a X5680.

I'm still waiting for 2 X5680 and a mini pcie 6 to 8 pin pcie cable to get my RX 480 Nitro 4GB working.

I got them for 395.00 for the pair on eBay. Have all the other tools because I'm an apple certified tech and work on them for a living. The processors are lidded so I needed some thicker thermal padding than what I had on hand. The x5680s may be a lot cheaper but I didn't look. But going from 2.26 8 core to 3.46 12 core should be a huge improvement for my workflow. I just wanted to max it out.

Also after reading several posts and direct source of amd I'm thinking the rx480 crossfire setup will work fine. As they say no risk no reward . Several benchmarks later this week and when I can get the second xfx rx 480 1338mhz in I'll update the results including fcpx testing. I'll monitor draw but from what I've seen the xfx cards are the best with stable MHz and lower power draw with zero fluctuation. Stay tuned

 

[theitsage]

With the one I have, I can fold the cable really flat directly out of the connector itself. It's very low profile. I'm not ruling out that there might be ones even lower, but I don't think I'll try another at this point.

Even if the cable gets routed to the side instead of upwards, there needs to be a clamp somehow. I'm don't see that it can be made much smaller. If you care to google and post pictures I can guesstimate if it'll fit.
[doublepost=1476736888][/doublepost]

I have an Apple original Nvidia 120 card laying around as fallback. But as long as the RX 480 boots to allow for .kext editing I'm good.

My 280X isn't flashed, so it adds no additional functionality.

Always good to have a fail-safe GPU. The GT120 is great for that purpose.
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The memory will run at 1333 once the processors are swapped


by default in os sierra at least for me it scales at 1920, however if you look at the other resolutions scaling works well. I dialed mine in at 3008 currently, my display is a Samsung uhd so not true 4K. I'll be upgrading it down the line though. I search google for the iMac 4K scaling options



I got them for 395.00 for the pair on eBay. Have all the other tools because I'm an apple certified tech and work on them for a living. The processors are lidded so I needed some thicker thermal padding than what I had on hand. The x5680s may be a lot cheaper but I didn't look. But going from 2.26 8 core to 3.46 12 core should be a huge improvement for my workflow. I just wanted to max it out.

Also after reading several posts and direct source of amd I'm thinking the rx480 crossfire setup will work fine. As they say no risk no reward . Several benchmarks later this week and when I can get the second xfx rx 480 1338mhz in I'll update the results including fcpx testing. I'll monitor draw but from what I've seen the xfx cards are the best with stable MHz and lower power draw with zero fluctuation. Stay tuned

I'm curious the see how well the XFX OC cards run vs. Reference cards. Here's my results with a pair of Sapphire RX 480 XFire in post #46. Make sure you turn "Compatibility Mode" ON - this is the hot fix to prevent drawing more than 75W from the slot.

 

[wickerstick]

Always good to have a fail-safe GPU. The GT120 is great for that purpose.
[doublepost=1476798494][/doublepost]

I'm curious the see how well the XFX OC cards run vs. Reference cards. Here's my results with a pair of Sapphire RX 480 XFire in post #46. Make sure you turn "Compatibility Mode" ON - this is the hot fix to prevent drawing more than 75W from the slot.

will do! if you haven't yet seen the video of the XFX RX 480 from jays2cents he tests it under load at stock clocks and again overclocked. albeit in windows, still very impressive. I will be mimicking his testing to see if his card was "special" or not. I believe his was clocked as 1288Mhz vs mine at 1338Mhz stock clocks. So far the only game i tested was CS GO at full res everything max and the single cards ran like butter! (windows) still lots of testing to do and my thermal pad says it will arrive between the 21st and 28th :^(

 

[lowendlinux]

will do! if you haven't yet seen the video of the XFX RX 480 from jays2cents he tests it under load at stock clocks and again overclocked. albeit in windows, still very impressive. I will be mimicking his testing to see if his card was "special" or not. I believe his was clocked as 1288Mhz vs mine at 1338Mhz stock clocks. So far the only game i tested was CS GO at full res everything max and the single cards ran like butter! (windows) still lots of testing to do and my thermal pad says it will arrive between the 21st and 28th :^(

I might be able to do it before you since I just got mine and am now going through the process of dealing with the nVidia to AMD transition in Linux and hack

 

[theitsage]

The more the merrier!

 

[lowendlinux]

This and the following will be Linux since I need to figure Clover after changing GPU's which I'll probably do in Thursday since tomorrow is dedicated to Jeep u-joints.

So Luxmark
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and finally

 

[theitsage]

Polaris drivers in Linux are much better.

 

[lowendlinux]

but the GPU is still not recognized which is strange since these drivers have been out since July

 

[Eateroffoods]

Always good to have a fail-safe GPU. The GT120 is great for that purpose.
[doublepost=1476798494][/doublepost]

I'm curious the see how well the XFX OC cards run vs. Reference cards. Here's my results with a pair of Sapphire RX 480 XFire in post #46. Make sure you turn "Compatibility Mode" ON - this is the hot fix to prevent drawing more than 75W from the slot.

Sorry, i'm new to here and the mac os in general. Where would I go to turn Compatibility Mode on?

 

[wickerstick]

Sorry, i'm new to here and the mac os in general. Where would I go to turn Compatibility Mode on?

I believe he is referring to a amd driver patch on the windows side of things. The only way to fix the pcie power on the Mac side is to modify the bios of the card. There is a post several pages back with a link to overclockers site where they have done just that.

Small update I ordered the second oc xfx rx 480 tonight and will be arriving in a couple days. I'm also replacing my 250gb ssd(windows) with a second 960gb ssd. This is buy far the craziest build I've ever done! I may make a post going over the build and everything in detail soon!

 

[theitsage]

I was expecting another beta release of 10.12.1 yesterday but instead we heard about Mac event on the 27th. Gotta wait 2 more weeks to see whether there's improvement to Polaris drivers when Apple officially sells Macs with these GPUs.

My Alienware Area 51 is fully up and running with a 3-way CrossFire RX 480 in Windows 10. With the latest drivers, Heaven running at 1080 DX11 Extreme settings got 144.7 FPS. GTX 1080 got sub 110 FPS.

3 x RX 480 > GTX 1080 > 2 x RX 480 > GTX 1070 > GTX 980 Ti > RX 480/GTX 980 > RX470/GTX 970

 

[lowendlinux]

Remember that just in benchmarks though games have to be coded for crossfire/SLI

 

[theitsage]

I'm aware of that. Valley actually does not handle 3-way CrossFire very well - almost same score with 2-way CrossFire.

 

[lowendlinux]

I'm aware of that. Valley actually does not handle 3-way CrossFire very well - almost same score with 2-way CrossFire.

I installed Windows this morning before heading to work so when I get home I'm going to check to see if any of my very few games supports CrossFire. If they do I'm thinking I'll pick up a second card also.

 

[kalisz]

Well the xfx gtr fits really tight in my mac pro, I mean this tight I'm still concerned if the graphics card pcb won't break at some point... At any other aspect it is really great, the power usage in windows after 1350/2200 OC is about 120W and fans not spinnig when idle is awesome feature. I have not encountered any issues in macOS so far. The xfx gtr was cheapest option in my country but if I could I would buy the msi version as it has detachable backplate and wouldn't have to worry about breaking any fragile parts.