Author Topic: Render Very Slow  (Read 369 times)

2023-10-26, 20:47:56

PTMV

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Could friends help me? I was noticing that my rendering for large scenes takes a long time, like the total rays are no more than 1.3, taking hours to clean up the noise, I only have 32 GB of RAM, and my processor is an Intel 5930K Very old, do you think that increasing my memory to 64 GB of RAM, which is the maximum that my card supports, would improve this performance? Or just upgrading the new processor and adding 126 GB of RAM?

2023-10-26, 21:12:47
Reply #1

romullus

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If your system is running out of RAM during rendering and Corona has to use swap, then yes, adding more RAM would dramatically increase render speed, otherwise more RAM does not lead to more speed. On the other hand more powerful CPU will always mean more speedy rendering.
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2023-10-26, 21:51:59
Reply #2

PTMV

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If your system is running out of RAM during rendering and Corona has to use swap, then yes, adding more RAM would dramatically increase render speed, otherwise more RAM does not lead to more speed. On the other hand more powerful CPU will always mean more speedy rendering.

for example, this scene didn't show a lack of ram but I found the total rays to be so low with this value of 1.227, shouldn't it be above 2.0 to be faster?

2023-10-26, 22:54:15
Reply #3

romullus

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Not necessary, rays/s by itself doesn't mean much. It's useful when you want to compare how exactly the same scene renders on different computers, but if you want to use it as scene performance metric on your pc, then it's not so much useful. You can easily inflate this number several times and the scene will actually be rendering slower - just add few materials with Corona AO to significant portion of your scene objects, crank its quality to the max and watch what will happen :] 1,2 M ray/s might be on the lower side, but it's nothing out of ordinary, especially for quite old CPU like yours. I'm not saying that your scene can't be optimized to render faster, but ray/s is not the best metric to look at in this case. Rays/sample is more useful in trying to determine if a scene has an issues and in your case this number is very good.

You're rendering to a set number of passes - your scene is barely reached half way, but it's already at 5% noise level. Consider rendering to the noise target and use denoiser to clean residual noise.
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2023-10-28, 11:01:34
Reply #4

romullus

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I've been rendering couple different scenes today and paid attention to their rays/s metrics which i usually don't do, because that doesn't make much sense to me. One scene was an exterior with simple lighting, it rendered very fast and had about 2 M rays/s, another scene was interior with relatively complex lighting and materials, it rendered much much slower and had about 16 M rays/s. As you can see, rays/s on it's own tells nothing about how scene performs.
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2023-11-10, 10:58:01
Reply #5

maru

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As Romullus mentioned:
- If you are not exceeding the available RAM limit, then adding more RAM to your machine will not result in faster rendering.
- If you are exceeding the available RAM limit, then you can either optimize your scene to use less RAM or add more RAM to your system and both things will result in faster rendering.
- Rays/s can tell us something if we are rendering the same scene on two different machines. Then we can tell which one is faster. Or if you have two identical systems and one is getting a lower ray/s number than the other - this means that something is wrong with it. Other than that, the exact number of rays/s is dependent on the scene you are rendering and can range a lot.
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