Rhino 6 Raytrace with two GTX 1080

Hi all. when I monitor my GTX 1080 activity during Rhino Raytrace Renders there is no increase in activity or temperature. How can I be sure Rhino is taking advantage of my render cards ? Are there any special settings ?

Look in Rhino Options > Cycles > Device settings:



@nathanletwory explained somewhere that the way cycles is integrated in rhino does not allow for any performance gains by using more than one GPU. so the way I understood it was that wether you use one GTX1080 or two, it does not make any difference (in terms of renderspeed).

use the one GTX1080 for cycles that is not your display card. use the other one, because it is 100% not utilized by displaying the viewport or other stuff you might do as well. so there is still some advantage you get from using two cards.

I did not say that.

If you have two of the same model GPU you’ll see a little under twice speed improvement.

If you on the other hand have a low-end GPU and a high-end GPU then you’ll see a little under twice the speed of one low-end GPU.

Two GTX 1080 cards will be like two GTX 1080 cards (a little under, but still).

So if you have a GTX 760 and a GTX 1060, both selected in the options, then it’ll be like having two GTX 760 cards.

oh, then I misunderstood that.
anyway, that’s great! now I think I know what to buy next :slight_smile:
thanks for clearing that up.

just wanna know if I understood this correct now…

so I have an RX580 and a Vega64 in my workstation atm. benchmarks for compute and rendering show the vega64 deliveres roughly double the performance of the RX580. let’s assume I would replace the vega64 with another RX580, so I’d have two of those in the system. If I would let them both do the cycles rendering then I could expect roughly the same performance compared to letting just the one vega64 do the rendering, is that logic correct?

thanks for clarifying.

That’s the way I understood this, yes…

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ok, thanks, will probably replace the vega64 with another rx580 then. less power consumtion and much less noise. also the vega64 needs a lot of tinkering with undervolting and clockspeeds before it is able to keep its clockspeeds without throtteling while rendering for a longer period. I did all that, was fun, but the vega is just not a well rounded product imo.

vegas and other amd cards like rx570 and rx580 are just dirt cheap on ebay atm.

You get a little under twice the RX580 speed, yes.

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Have sold the RX Vega and gotten a second RX580 instead (cheap on ebay). indeed, rendering the same scene takes about the same time with the two 580s compared to the single vega64. damn that vega was so loud, the 580s fans normally don’t spin at all and keep quiet while rendering.

had done this swap quite some time ago, but didn’t had the time to post. will share some more once I have more time.