Titan Z vs Titan Black for GPGPU

tiger10guy

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May 3, 2014
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I'm still working on the build I asked about in http://www.tomshardware.com/answers/id-2129303/titan-asus-z87-gpgpu.html.

I'm building a desktop for scientific computing with 3 GPUs. I was going to buy 3 Titan Zs (if they come out soon), but I have one more question before committing to that.

For one Titan Z do the GPUs show up as two separate cards? The biggest question is whether or not I can start 1 kernel that uses 12GB of memory (even if it only uses 1 GPU) or whether I can only start 2 kernels on different GPUs if I want to use all 12GB.

If I can start 1 kernel that uses 12GB then I'll get 3 Titan Z's. Otherwise I'll get 2 machines with 3 Titan Blacks each.
 
Solution
As far as i know, you can't really use the 12GB of memory on the card, you're limited with 6GB. Everything in those dual GPU cards works mirrored, so you can't just disable one GPU and work with all the memory.

I don't even know if you can disable one of the GPUs, because they connected through some kind of controller that dispatches the work (or something like that).

For what do you need 3 Titan Z anyway? Haha!

By the way, it was postponed again.

Saludos

Kekoh

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Yeah, they show up as 2 different cards, at least with dual gpu AMD cards. I assume Nvidia cards would be the same way.

Just to clarify, they won't be in SLI right? SLI is limited to 4-way SLI, and 3 Titan Z's would be 6-way.
 

tiger10guy

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Right, they won't be in SLI.

So that means I can't start 1 kernel which uses 12GB of memory, right?

Edit: added the question
 

Kekoh

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I'm not sure. free bump
 

Brunostako

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As far as i know, you can't really use the 12GB of memory on the card, you're limited with 6GB. Everything in those dual GPU cards works mirrored, so you can't just disable one GPU and work with all the memory.

I don't even know if you can disable one of the GPUs, because they connected through some kind of controller that dispatches the work (or something like that).

For what do you need 3 Titan Z anyway? Haha!

By the way, it was postponed again.

Saludos
 
Solution

tiger10guy

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Thanks Kekoh and Brunostako!

We'll probably go with Titan Blacks since the Titan Z doesn't do exactly what we want and is more expensive.

The Titan Zs would have been useful because because we could fit more compute capability in one machine. e.g. running a GPU process that needs more than 6GB of memory isn't an absolute requirement, but it might have been useful. We have a K40 to play around with if needed.