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2x GTX 1070 and Vram

Posted: Mon Nov 28, 2016 3:26 am
by shinotoy
Hi everyone,

I plan to buy Octane and switch from Mac to Windows. I am currently looking for a PC configuration and I might go for a GTX 1070 8go as GPU.
Now I have several questions :

If I buy a second GTX 1070 8go, i will have to connect one for my display. As I heard Octane only consider the GPU with less Vram, I was wondering even both of my card have same 8go, will octane consider the one that is used for display (so it wont be 8go but less) or the other one dedicated to rendering ?

Because i feel it is a shame to disable 1x GTX 1070 in order to let the other one focus on the rendering. So i must be sure that if i use both, with Priority Low, and use priority on one of the GPU, octane will still let me be able to use the full 8go.

I don't know if I am clear enough. Anyway if im not, just tell me ;)

Thanks,
Jeremy

Re: 2x GTX 1070 and Vram

Posted: Fri Dec 02, 2016 10:10 am
by had
Hi Jeremy,

The priority you use on a card has no effect on the vram. Which means with 2x1070, octane will have a 8 go vram and the card with low priority will be running at 75% speed and the other 100%.

My home computer will probably be the same rig; 2x1070.
What I have now is a very cheap $30 card which is connected to my display which is totally disabled in octane this way the two 1070 run at 100%.

But with some usage experience I would not recomand to have such a shity card leading the display since it s rubbish when you want to use gpu based application such as substance. And obviously when you will have more cards you will throw it away to get an extra pci express port. I read the gtx 10xx where actually less of on issue to not have a lagy display when running, anyone know about that?

One last thing which matters is the cooling, if you don t plan at all to have more than 2 gpus I guess it s okay to have this custom top fans, just leave an empty pci slot between them. But if you plan to end with 4 gpus then go for the founder edition which blow the hot air outside instead than on top (which would be a gpu). The best (but pricey) option is to go watercooling or hybrid (msi sea hawk). But hybrid would be tricky with 4 gpus since you need space to attach the external fans.

That s pretty much it,
Best,
H.

Re: 2x GTX 1070 and Vram

Posted: Sun Dec 11, 2016 10:05 am
by shinotoy
Hi Had,

Wow, sorry to answer late but thank you very much for these long and clear explainations !
I now have a last question, just in case you could answer.

What PSU would you recommend for 2x GTX 1070 ? I got my eye on a computer with 650w. Is that enough ?

Thanks ~
Jeremy