OTOY Forums

Uhlhorn wrote:Are You using two power supplies? You should use only one! It’s better.

And this is one of those statements I keep hearing, "its better just because." Is there any proof that it actually is?

The Akitio comes with its own power source, so why not use that if your GPU is already powered by an alternate PSU? What is really the problem with two power sources?

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.