Question about hybrid rendering

[Danielhruby]

I have a 2013 Mac Pro with D700 GPUs. I am wanting to buy a new PC to 1) add more processing power to my renderings. I will probably keep my work on the Mac and use the new PC as a secondary render node. 2) It will be nice to have a PC for software not available for mac. I am looking into getting a 16 core Threadripper with a Titan X GPU. My question is; will the secondary system contribute both CPU and GPU buckets back to the Mac machine? Or do I need to be using that PC as the Master and the Mac as a slave?

Is there any reason to go for a more expensive i9 18 core CPU?

Thanks

[nickjamesgordon]

Just assembled a 16 core Threadripper, running V-ray standalone. Very very fast.
Didn't bother networking, I just loaded the job (Modo) on that machine, booted standalone and went back to work on my nMP.

Marginal gains on the intel route, for a lot more cash.

[Danielhruby]

Nice. So you like it!. I was thinking of getting this system. It would include a TitanX GPU. I just want to make sure that if I do network, I could still do my work on the mac and use distributed rendering with both Threadripper CPU and the TItan X Cuda Cores contributing.

[Danielhruby]

Can anyone on the Chaos Dev team confirm there are no compatibility issues to achieve this Hybrid OS / Hybrid Rendering workflow?

[vladimir.nedev]

I don't think there are any compatibility issues, however:
I did some tests with the lowest spec mac Pro (4 core Xeon and D300 cards) and a Windows 10 machine with Ryzen 1800X, GeForce 750 Ti and a Titan V.

If you run the render from the mac Pro, with default settings, the Titan V and Ryzen 1800X are not fully utilized.
This most likely happens because of the additional overhead of having to send the rendered results through the LAN.
Fixing this requires increasing the GPU rays per pixel for the scene from the default 8 to something like 50 or above.
Increasing rays per pixel generally leads to lower interactivity, as the image is updated less often.

Using the mac Pro's CPU actually lead to lower overall rays per pixel reached within 1 minute.
However, I ran only one test, so it could be due to the nature of the scene.

In any case, the mac Pro's CPU is probably more than 10 times slower than a Titan GPU, so it won't be doing much.

Other caveats:
- when running a V-Ray Standalone as a GPU slave, you have to use the external tool to set the CUDA devices (to enable the Threadripper), the V-Ray preferences inside Modo affect only the GPU engine running inside Modo or V-Ray Standalone started through Modo
- some changes in RT are not picked up on the render slaves, when you are using RT + DR like in your scenario, so you will have to restart the render, this is a V-Ray for Modo specific problem, but is low priority to fix. It's mostly changes to mesh data, like changing vertices, edges, polygons or assigning new material/part/selection tags.

Overall, I think you will have a better experience if you use the new Windows machine as your workstation.
But to be sure you will have to run these tests on your particular machines and network.

Greetings,
Vladimir Nedev

[Danielhruby]

Vlad,
Thank you so much for doing some tests! I really appreciate it.

So you think that switching the Ryzen to be the master might allow the mac to contribute to the render more seamlessly?

For the cost of this Threadripper build, I could purchase two more 12 core MacPro cylinders and have a small ALL mac farm. Great for me in that I am 100% mac person now. I just thought it was wise to have a PC in the mix here for various reasons, although I am a bit intimidated about figuring out the networking nd system management on the Windows 10 Pro side of things. Maybe it is more like a Mac experience now?

Pros for ALL Mac:
Hardware is familiar
OS is familiar
Networking is easy
Distributed Rendering "Should" work correctly

Cons for ALL Mac:
No GPUs are used for rendering (Crazy!)
I'll be locked in to 12 cores and 64GB ram with no expansion options. (Is there a GPU Box I could connect to my all mac system?)
I still am limited to mac only software, Although I could maybe make one of the Macs a Bootcamped PC)
I am still working with 2013 technology. I like to be on the cutting edge, as long as it works!
Managing OS and software updates on 3 machines vs. 2

Pros for PC:
Latest and greatest tech
Plenty of room to add more GPUs
Let's me utilize PC Only software, like Revit, if I need to.
Better hardware value for $/Second of rendering. (?)
Only need to manage OS and Software on 2 machines.

Cons for PC:
Sounds like the network rendering will not be a "point and shoot" experience.
I might be jumping around from Mac to PC a little more than I expected.
I need to learn Windows, Networking, and whatever else might plague a hybrid farm.


Vlad (or anyone else with some insights/experince with hybrid networks)
, what are your thoughts on the situation? I am certainly not afraid to work on the Threadripper as I think the single core performance will make my workdays in modo more pleasant. But I am primarily trying to increase the productivity of Rendering, including RT on the master system. IN fact, I really want to see RT running like realtime with both machines pushing the speed.

Thank you

[vladimir.nedev]

So you think that switching the Ryzen to be the master might allow the mac to contribute to the render more seamlessly?

I haven't tested this combination.
But the mac Pro CPU will probably not contribute much next to a Titan X, and the fact that it's accessed through the network can bring you additional problems, like the RT updates, having to increase rays per pixels, etc.

Vlad (or anyone else with some insights/experince with hybrid networks)
, what are your thoughts on the situation? I am certainly not afraid to work on the Threadripper as I think the single core performance will make my workdays in modo more pleasant. But I am primarily trying to increase the productivity of Rendering, including RT on the master system. IN fact, I really want to see RT running like realtime with both machines pushing the speed.

We have IT guys here, so I don't know how hard it is to setup the network.
We have static IP addresses, which makes it very easy to setup connections between machines even if they are using different OSes.

My personal opinion is that, if you want to do GPU rendering, you should go with just the Windows machine, and sell the mac Pro.
If you can't stand Windows, maybe just go with a few mac Pros and use DR + adaptive bucket rendering, it doesn't have the issues related to the progressive sampler and remote machine utilization.

Greetings,
Vladimir Nedev