vray rt DR GPU

[Rhys]

HI

looking at builidng a new rig just to hold 3 x 980 gtx we would want it on the network so that everyone can access it when using RT and distribute to it. As our local graphics cards are 780gtx powering 2 monitors and using RT kills the local graphics!

So my question is would we get pretty much the same performance using RT over a network then having it locally in the workstation? And does RT have any speed decrease when running in 3 x sli mode?

[vlado]

So my question is would we get pretty much the same performance using RT over a network then having it locally in the workstation?

If you have a gigabit network, it will be mostly ok. I can try to do some experiments and get you more specific numbers later if you are interested.

And does RT have any speed decrease when running in 3 x sli mode?

It runs fine. SLI is not needed, actually (perhaps might be better to disable it) - V-Ray RT will use the cards anyways.

Best regards,
Vlado

[Rhys]

Hi Vlado,

Yes would be great to know! It will all be through a gigabit network. It will actually be 4 x 980gtx that will be in there. Thought we would see what all this gpu fuss was all about !

[vlado]

So I made a test rendering the attached scene on my machine with 2 x GTX 980.

I rendered it in two ways: first with my local machine running 3ds Max and rendering on the same machine. The render time for 1015 samples was 10m 54s. The second render was done by running 3ds Max on another machine and using my machine as a render server for the GPUs. The remote machine itself did not participate in the rendering. The render time for 1015 samples was 9m 26s, network usage was about 125 Mpbs

This result was a bit surprising - I would have expected the local rendering to be faster. I'm not sure if the 3ds Max GUI is getting in the way or something - need to do more experiments. In any case it looks like network DR rendering is working well.

Best regards,
Vlado

[Rhys]

Thanks Vlado, agree would of expected local to be faster. As the remote machine wouldn't be powering any monitors as such maybe its the overheads of the local machine.

So on network usage, that was pretty much maxing out the 1gb network? so may need to team a network card just to not loose any overheads.

[vlado]

So on network usage, that was pretty much maxing out the 1gb network?

The traffic was 125 Mbps, so way below the 1 Gbps limit. Even if it becomes a problem, there are ways to adjust the network traffic using the ray bundle size/rays per pixel parameters, so this is not such a big problem, it seems.

Best regards,
Vlado