Mac Pro 2013 and GPU Expansion

Question

zachi Author

Level 1

7 points

Mac Pro 2013 and GPU Expansion

Dear Apple,

There are a lot of discussions in the net about wether it is possible

to attach modern highend GPUs to your new Mac Pro.

Can you please clarify if a Thunderbold 2 connection is capable

of transporting the full bandwidth of one or more PCIe 16x GPUs

(Nvidia Titan for example) attached in an Expansion Box,

or if Thunderbold 2 is too slow and will cap the bandwith.

This question and if there is a dual Processor Version will decide

if the new Mac Pro is usable for 3D rendering or not. In other

words if a whole industry is forced to switch to Windows.

best Regards,

zachi

Posted on Jun 13, 2013 10:26 AM

Reply

Answer 1

May 24, 2014 8:52 AM in response to zachi

RE: PCIe Bus speed in Bytes/sec

PCIe Bandwidth Comparison (Each Direction)
PCIe 1.x	PCIe 2.x	PCIe 3.0
x1	250MB/sec	500MB/sec	1GB/sec
x2	500MB/sec	1GB/sec	2GB/sec
x4	1GB/sec	2GB/sec	4GB/sec
x8	2GB/sec	4GB/sec	8GB/sec
x16	4GB/sec	8GB/sec	16GB/sec

--courtesy netkas.org

ThunderBolt-2 is 20Gbits/sec, or 2.5G Bytes/sec. That appears to be faster than a PCIe 2 4x slot. Not a 16x, but not too shabby.

.

Reply

Answer 2

zachi Author

Level 1

7 points

May 24, 2014 11:33 AM in response to Grant Bennet-Alder

i waited for you to defend the "pro" 😀

i m not a technician, but if you do GPU rendering you need fast transfer to and from the GPU. from what i read it works with thunderbolt but sending big scenes will be slower compared to a PCIe 3.0 16x connection (which is standard on a modern pc).

but as said: this is not the show stopper in real world use, the costs are.

Reply

Answer 3

May 24, 2014 12:15 PM in response to zachi

i waited for you to defend the "pro" 😀

That is not something I ever cared to debate. I much prefer to discuss "meaningful performance" and "how to connect".

You were having the Pro/not-Pro disagreement with other posters on those previous discussions.

Reply

Answer 4

Q.A.

Level 1

0 points

May 25, 2014 8:08 AM in response to zachi

Thanks for chiming in :-)

"for the new "pro" you need a thunderbolt2 model, which has a slower throughput."

Yes, and that's why I'm not considering Thunderbolt 2 as an option, but I remain hopeful for Thunderbolt 3.

Of course we'll need a Mac Pro update that supports it, but that realistically may happen by the time I need a new workstation.

"but reports say this works, and there are a few products around."

Please elaborate. What products should I be keeping an eye on?

Reply

Answer 5

watzlav

Level 1

19 points

May 25, 2014 11:29 AM in response to zachi

I'm really looking forward to the WWDC in a week. I hope Apple releases a new NVIDIA powered workstation, I'd even buy a fully bulked up iMac at this point, but the mobile graphics are really killing the deal…

Reply