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Rendering with Arnold in 3ds Max using the MaxtoA plug-in.
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Time to first pixel Arnold GPU

9 REPLIES 9
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Message 1 of 10
pixelsim
330 Views, 9 Replies

Time to first pixel Arnold GPU

Sorry repeated from the Shading lighting and rendering forum, I missed the arnold specific one.

 

Hi there

I realise I am asking a question that is difficult to answer as there are so many variables.

But

Myself and colleague have latest Arnold version 5.6.6.1 and latest nvidia drivers 546.33 (studio) and Max 2024.2.

One has a rtx 4090 with threadripper 32 core cpu

One has an rtx 4070 with ryzen 16 core cpu

We are testing the exact same scene on both machines to test GPU rendering as it has had an overhaul.

 

One of the differences is that the 4090 is about 4 times slower to get to any first pixel when starting a render or using ipr.

Also when selecting a region to render when ipr rendering the 4090 is again around 4 times slower to update and start rendering the region.

 

So question is, anyone have any idea why this might be?

What makes getting to the first pixel so much longer on a much more powerful GPU?

Is it simply the fact that the 16 core ryzen has faster single core power?

 

Thanks for any insights, ideas, again I realise its not an easy question to answer

9 REPLIES 9
Message 2 of 10
Stephen.Blair
in reply to: pixelsim

The best place to start is with some detailed Arnold logs. Start a new 3ds Max session. Set the verbosity level to Info (Render Setup > Diagnostics). Open Render Message Window. Open Arnold Render View and render.



// Stephen Blair
// Arnold Renderer Support
Message 3 of 10
pixelsim
in reply to: pixelsim

thanks

Here are the render logs for the two different cards.

Simon

Message 4 of 10
thiago.ize
in reply to: pixelsim

If you repeat this with CPU renders, do you also find the 4090 machine is slower to first pixel? I am wondering if this even is a GPU issue. For instance, I noticed the 4090 machine took much more time to do what looks like non-GPU setup work.

If you do the CPU-only test, can you also bump the log verbosity up from info to debug?

Message 5 of 10
pixelsim
in reply to: pixelsim

Hey thanks

Of course its possible its not a gpu issue, this is just the first time we have noticed the delay, as we were doing direct comparisons

I will do the new tests thanks

Message 6 of 10
pixelsim
in reply to: pixelsim

Hi again

here are the logs when using cpu. As far as I can tell there is still a large difference in set up time, so as you said may not be a GPU issue.

Hope you have some suggestions as to what I could try next

Thanks

Message 7 of 10
pixelsim
in reply to: pixelsim

Hi

is there any more advice on this? Be good to know how to reduce set up times on the 4090 machine

Thanks

Message 8 of 10
thiago.ize
in reply to: pixelsim

The logs make it look like maybe this is the scene export that is slow. Unfortunately there is no logging information for scene export, so it's hard to know for sure. The 4090 took 22s while the other machine 3s. Why that would be so much slower I do not know.

Message 9 of 10
pixelsim
in reply to: pixelsim

ok thanks

what happens on scene export so I can see if there is anything I could do?

Message 10 of 10
thiago.ize
in reply to: pixelsim

If you want to investigate further, you can output a profiling file (under the arnold diagnostics tab) which will likely tell you what is happening. You can look at them in tools like https://www.speedscope.app/. If you post them here, maybe someone else can also help you out with it.

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