Dual eGPU setup working on nMP + FCPX fix + Pictures via Instagram  

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Yukikaze
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Joined:10 months  ago
Posts: 496
March 20, 2017 12:14 pm  

They aren’t easy to find. I’ve encountered them at work before, typically around prototype hardware, and also in servers. Rack-mounted servers use there to re-orient a single vertical PCIe slot on the motherboard into multiple slots horizontal, in parallel with the motherboard, to reduce the server height.

I tried to take a look at ebay, and saw exactly one (aside of cheap Chinese ones with PCIe x1 slots, like this). This is from a Supermicro server. The chip under the green heatsink is the PCIe switch that multiplexes traffic downstream to the three PCIe slots. No idea what the blue slot is. No idea if that will work for you in any way. It should work with any PCIe slot, as PCIe defines a switch standard, but that is in theory, as I have no idea if there’s any Supermicro magic going on behind the scenes.

The ones we use at work are pretty damn expensive, and usually manufactured on order, so I am not sure they are “consumer” devices in the sense that you can buy them off the shelf.

"Dire Wolf" - HP ZBook 15 G2: Core i7-4810MQ, 16GB DDR3 1600Mhz, K2100M dGPU, R9 Fury eGPU (AKiTiO Thunder2 over TB2), HP Z27q (5K) + Dell P2715Q (4K).
"Stormcrow" - Lenovo T430s: Core i7-3520M, 8GB DDR3 1600Mhz, GTX1050Ti eGPU (AKiTiO Thunder2 over TB1), Sony 4K TV.

“Always listen to experts. They'll tell you what can't be done, and why. Then do it.” - Robert A. Heinlein, "Time Enough for Love"


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imcalledandy
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Joined:9 months  ago
Posts: 92
March 31, 2017 5:43 am  
Posted by: benr

Hey Andy, any chance you can try daisy chaining the two cards at some point, see if you get the same CUDA and Octane/Cycles performance? Also, do you use DaVinci Resolve? Would be curious to know about that too if you do.

Hey @benr I don’t use DaVinci Resolve I’m afraid but I can confirm that daisy chaining the eGPUs works!

Performance in the IPR seems to be pretty good too.

However, when I gave Cycles a really heavily displaced scene, rendering at 2000 x 2000 it appeared to fall back to the CPU rather than Multi-CUDA. I wonder if it couldn’t see all the available VRAM?

Does anyone know how many eGPUs we could potentially hook up then? I’m guessing at least 2 more…


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imcalledandy
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Joined:9 months  ago
Posts: 92
March 31, 2017 5:49 am  

It definitely appears the eGPUs aren’t using all the available VRAM for rendering when daisy chained, so I’ll revert to my previous setup.

 


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benr
 benr
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Joined:9 months  ago
Posts: 27
March 31, 2017 1:34 pm  

Brilliant, many thanks for testing, Andy.


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imcalledandy
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Joined:9 months  ago
Posts: 92
April 1, 2017 1:49 am  

@benr – I now believe that I’d set the level of displacement far too high because Cycles switched to CPU rendering when I had the same scene in my usual configuration. I’ll test again with lower settings next week and let you know. 


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barefeats
Active Member
Joined:8 months  ago
Posts: 11
April 15, 2017 7:27 pm  

I have dual eGPUs running on the 2016 MacBook Pro. However, when I hook the same two eGPUs to the 2013 Mac Pro (TB2 Bus 0 and 1), it won’t boot up. It boots fine if I connect one eGPU at a time. 

What am I missing here?

BTW, I’m running the 1080 Ti in one eGPU and the 1080 in the other eGPU.

Edited: 5 months  ago

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nycjunglist
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Joined:4 months  ago
Posts: 6
June 2, 2017 7:56 am  
Posted by: barefeats

I have dual eGPUs running on the 2016 MacBook Pro. However, when I hook the same two eGPUs to the 2013 Mac Pro (TB2 Bus 0 and 1), it won’t boot up. It boots fine if I connect one eGPU at a time. 

What am I missing here?

BTW, I’m running the 1080 Ti in one eGPU and the 1080 in the other eGPU.

I’m having similar issues with my nMP as noted here: https://egpu.io/forums/mac-setup/two-egpus-nmp/

@imcalledandy What exactly did you do to get your machine to boot with both GPUs connected?


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imcalledandy
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Joined:9 months  ago
Posts: 92
June 2, 2017 12:52 pm  

@barefeats and @nycjunglist – Have you tried using -a mode?

I had to do that when I was experimenting with 3 x eGPUs with my nMP – 2 x Thunder 2 and 1 x Node.

I had mixed success and I believe I’ve tracked it down to the 1080Ti card being a Founder’s Edition – the nMP doesn’t seem to like those so I’ll get a non-reference card and test the 3 x setup again – more on that here:  https://egpu.io/forums/mac-setup/can-you-mix-9-series-with-10-series/

Back to the point: try enabling -a mode in automate-eGPU and put your eGPUs onto different busses – i.e not bus 0. I found with my attempt at 3 x I had overcrowded Bus-0 as I had an HDMI connection running too.

BTW – I did get the Node and a Thunder 2 working

 

Edited: 4 months  ago

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nycjunglist
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Joined:4 months  ago
Posts: 6
June 4, 2017 3:18 pm  

@imcalledandy Well, I gotta say, I think that worked!

I ended up reinstalling the script twice since I didn’t uninstall the web drivers the first time. I let the script download them the second time which seems like it allowed the script to take care of some remaining tasks. After my first attempt, the cards were showing up as Nvidia Chip Model which I knew was wrong and led me to my second attempt. I have 1 card and 1 display in Bus 0 (ports 5 & 6), and the second card in Bus 1 (first port).

There’s a post you left in that other thread where you mentioned you plugged in your display AFTER you booted up. I took a cue from that and left my monitor off during startup and everything worked as expected. I’m not 100% sure if this is one of the tricks needed, but I was initially having startup issues with my monitor on at boot and both devices connected. I now have my second monitor in Bus 2 (2nd port) — connected after login — and everything is up and running.

I need to see whether or not having the displays powered on at boot causes that to fail.

Edited: 4 months  ago

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Supaiku
Eminent Member
Joined:5 months  ago
Posts: 40
July 3, 2017 10:09 am  

Just joining this thread as I am thinking about potentially setting up dual eGPUs on my 2013 iMac. I just recently got a GTX 980Ti to work with the Akitio Node. I’m not super hardware savvy and this talk about daisy chaining and risers and whatnot is kind of confusing to me. But based on what everyone has been testing here, do you guys think that 2 Akitio Nodes would work on my iMac? Also seems like I wouldn’t necessarily need to get the same card. I use Octane in C4D pretty heavily and I am LOVING the boost I get with the single eGPU (soooo much faster than things were before just using the internal GTX 780M), so they thought of it being even faster with a 2nd eGPU is making my mouth water 🙂


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