OTOY Forums

Netstor said:

Host Requirement
One PCIe 3.0 x16 slot and system has sufficient PCIe resources
Note:
1. The tower MacPro under 10.9 Mavericks and 10.10 Yosemite only supports up to 2 nVidia GPU cards.
2. Now the tower MacPro under 10.11 El Capitan is able to support up to 3 nVidia GPU cards again.

found on: http://www.netstor.com.tw/_03/03_02.php?MTEx

You don’t need many AKiTiO boxes, You also can put a splitter into Your AKiTiO box:
http://amfeltec.com/products/flexible-x ... -oriented/

I am actual using one GPU with this splitter. My second GPU is ordered today. I want to connect the second GPU to this installation.

That splitter looks cool, will there be any bottlenecks compared to daisy chaining TB? I also don't see it for sale in the US. I haven't been able so far to find any examples of multiple card TB setups, other than the dual Titan Z (https://www.techinferno.com/index.php?/ ... 10-nesone/). It would be an elegant solution if it weren't so expensive. Maybe I'll just go ahead and start adding cards + move them to other computers when I hit a limit, but I would have thought by now someone would have tried this scenario.

@chanson78 - read through nando4's thread on techinferno https://www.techinferno.com/index.php?/ ... b2/&page=1 Somewhere in there is a very good discussion of the 2 psu problem. There are also threads on how to alleviate the heat on the wires. Unfortunately for all of us noobs we have to read through a lot of cruft to get to the solid advice, and things change quickly. A common thread is the lack of shielding on the cheap bitcoin riser extenders. The consensus seems to be to either purchase a $100 properly shielded one, eliminate it by plugging directly into the Akito, or (I think) get the angled extender.

Perhaps the Thunderbolt 1 itself is the bottleneck. Than I would have bought the GPU for nothing.
Or it is running, but the scene upload to the GPUs needs longer. Who knows …

You can daisy chain Thunderbolt, but do You want to buy multiple PCI boxes, multiple power supplies and multiple raiser?

My Octane was producing many kernel panics. I removed the GPU splitter, and the kernel panics are gone.
So, do not buy the splitter until this issue is investigated and solved.

Update: Amfeltec says, that the AKiTiO box does not support switched splitters.

Uhlhorn wrote:My Octane was producing many kernel panics. I removed the GPU splitter, and the kernel panics are gone.
So, do not buy the splitter until this issue is investigated and solved.

I did the external GPU route just to get me started but built a PC for the additional Graphic Cards.

Uhlhorn wrote:My Octane was producing many kernel panics. I removed the GPU splitter, and the kernel panics are gone.
So, do not buy the splitter until this issue is investigated and solved.

I've tried using Akitio + backplane (call it splitter as it takes x1 & splits into 4 x16 mechanical). Worked out fine.

Your issue might be cause by grouding & other things..- anyway, both Thunderbolt part & splitter itself sits in the path of signal & that's most likelly is the problem - these signals are very sensitive. You might end up needing a lot of tinkering to get this work as You wish =)

@ glimpse: Do You think a ground loop is the problem?

So glimpse, what would your recommendation be for expanding a mac thunderbolt 2 setup (attached to trashcan or powerbook) to 4 gtx 980ti cards?

1. Adding 4, daisy chained Akitos using the usual nando4 method (is this possible?)
2. daisy chained Akitos with titan z instead of 980ti
3. adding Uhlhorn amfeltec splitter (assuming I can find one in usa)
4. possible to add backplane to Akito TB setup? can it expand to 4 cards?
5. something else?

An alternative:
http://www.netstor.com.tw/_03/03_02.php?MTEy

Scroll to the bottom of the page, GPUs are supported.

@Uhlhorn Grounding does make a bit of a difference with splitters causing some issues even on PC builds. If You start messing with eGPU & adding multiple stages between Your computer & GPU, be sure to make the properly!

& by the way, that alternative is around 1k & still (without modifications) house only single GPU.

@Collider it's a tricky topic, 'cos with 4-5 GPus You getting into problems with OS..

If I were to build a a rig for myself, I would hook eGPU (akitio based for trashcan) & then setup render node with possibility to expand up to 4GPUs - this way I would have least amount of troubles.

You have to keep in mind that eGPU via Thunderbolt2 is a workaround, not soemthing officially supported (o very welcome from let's say apple side =)