Hi Guys,
given that I have a 7950X with 192GB of RAM, but I don’t understand how it is possible that a simple scene takes so long to reach 5% noise.
The scene is that of the academy, and I inserted a sofa taken from cosmos and the Wall Paint material following the video (only normal map and no displacement), a simple Sky with Sun.
Corona 11 release, Cinema 2024.1.0, Windows 11
6 minutes to render a scene with nothing at 1600x900.. how is this possible???
Tnx @ all
Because you are indoors Id say, try the same scene outdoors I bet its faster. Ram wont help you in this case since there is nothing in the scene.
If you suspect the timing is wrong check the benchmark scene with your CPU, if its on par then all is good.
Howdy! I would +1 James Vella here and would suggest first running the Corona benchmark just so we are sure your machine is performing as it should. Those 192GB of RAM on the AM5 platform might be affecting performance but we won’t know for sure until we can validate the score with other 7950x machines.
It is a beast of a CPU for sure though 
Also, glad you’re partaking in the Academy. Hope you’re enjoying it!
I am not saying that this is the answer, but it is possible that 100 passes is an overkill in this scene. Maybe 50 would be enough to reach good quality? That should render in about 3 minutes.
To reach 5% of disturbance which is a high percentage, 100 passes are needed… with your same reasoning, if I put 50 passes I would have 10% of disturbance… however, don’t you think it’s exaggerated for such a simple scene and especially at 1600x900px take all this time and all these passes to get to 5%? (note.. i have a 7950x!!! …grrrr)
Just a note that noise does not scale downward linearly with passes, but takes exponentially more passes to reduce noise by the same amount. It takes more passes to go from 6% to 5% noise than it does to go from 7% to 6% noise, and so on. So 50 passes rather than 100 may see you at 7% noise and not at 10%.
Also, noise is not an absolute measure, especially not when it comes to how it looks to the eye. Some scenes may look perfect at 8% noise, some might still seem a bit noisy at 5%. Judgment is needed there as to what noise value fits any given scene.
Another note that “it takes this long for an almost empty scene” - well, the renderer is still doing what is usually the hardest part, which is bouncing the light around - and most of this scene is lit by bounced light. Adding more to the scene doesn’t mean it will necessarily take longer to render, or not by as much as you might think based on this “nearly empty” scene. After all, other objects may actually reduce how much light is bouncing by absorbing it; plus more detail may mean that a higher noise limit is acceptable to the eye because there are other things that distract from / cover up / override the noise such as textures, variation, and so on.
Hi Thomas, as always excellent words, I agree with your reasoning.
However, the only thing that I would like to underline and point out (which perhaps you haven’t taken into consideration) is that the scene has a resolution of 1600x900px and not 4K in addition to the fact that if in a 7950x it takes 6 minutes to reach the 5%, in a normal workstation it definitely takes half an hour.
Also add that the scene (corona academy course) is composed:
In any case, I did the required tests (1600x900px) with today’s latest release (something has improved but only slightly):
-limit set at 50 passes, the render takes 3.09min and stops at a noise 6.70%. The scene is too grainy despite having activated denoise with radius 1 and amount 0.65.
-limit set at 5%, the render stops at 90 passes taking 5.49min and with the help of the denoise radius 1 and amount 0.65 it turns out quite clean.
Test render 3072x1728px with stop render set at 5% takes approximately 23min (if I were to hypothesize a 5 second video at 30fps it would take 55 hours with my workstation with 39 thousand cinebench points).
Wanna share the scene so others can check there’s nothing odd with it?
Tried the academy start up file and imported the same sofa from Cosmos, added a corona sky and sun and tried my best to match these to your render. I added my own concrete wall material and rendered to 1600 x 900 to 5% noise and it finished in 3 minutes 50 seconds.
My PC is a Ryzen 9 5900X with 64 GB on Windows 10, CInema 4D 2024.1.0 and Corona 11 RC3
Ran again on a Threadripper 3990X 128GB Ram through Team Render and that took 1min 32 seconds
I’ll share it right away, so we can see if you also have the same result.
you can download it at this link, https://we.tl/t-LzOKCjPi2S , I await your feedback
tnx @ all
It is right now, come to think of it. I haven’t looked before.
@MircoTosti Studio
I did a test with the Sky volume effect off (it is on in your scene) and my render time went down to 4 minutes 46 seconds, down from 11 minutes
yes, mine is the VFB that way too
I deactivated the Sky Volume affects and the render scene at 3.15min (in my 7950x, 4.46 min with which workstation 3990x or 5900x?).. OMG almost half, but it’s still too much in my opinion
4 minutes 46 seconds was on the Ryzen 9. I have just run it on the Threadripper 3990X and it took 2 minutes 4 seconds.
Threadripper 3990X 2nd run was 2 minutes 9 seconds
