I have studied the whole forum, I ask the creators of the engine to contact us because on any thread there is no answer about the fact that the engine works in Path Tracing mode only at half strength, solve our request!
My situation is like this, I have 3 absolutely identical computers, everywhere is I7 14700KF, 64 GB Ram, rtx 4070 super, SSD Samsung EVO 970 Plus 1TB, all these machines during the rendering through Movie Render Queue loaded only from force 1-10%, and the CPU works out of 20 cores only one, the eighth core. Whatever settings I put on anti-aliasing (512/2, 1024/2, 50/20) all leads to the same thing. There is a groom in the project, and because of low iron load I have to wait for rendering one picture in 4K with 50/20 settings for 50 minutes! 50 minutes picture, such a result is not even in arnold on weaker systems. At the same time when working inside the engine (in preview) the situation does not change, the processor is loaded only slightly more evenly, but not significantly, the video card works in peaks. Project on 5.3.2
What I tried -
Install Studio drivers from Nvidia - did not help
Prioritize in Task Manager - didn’t help
Change render settings - even more did not help
Test on other machines - same situation
Render on 5.4.2 - exactly the same situation, even the render time is the same
Enabling and disabling reference motion blur - didn’t help.
I tried all options, I did everything in my power, I’m sure that the problem is somewhere inside the engine code, for this reason it does not work to its full potential
What surprises me the most is, if the CPU is loaded to one core and the graphics card to 1 percent, how is the rendering even going? Why does Path Tracing even work on the CPU
After replace 4070 super to 3090Ti and change version to 5.4.3 I can get boost a 30 min per same frame!
4070 Super - 1 frame 4K 50X20 - 46 min 30 sec 5.3.2
3090Ti - 1 frame 4K 50X20 - 13 min 30 sec 5.3.2
3090Ti - 1 frame 4K 50X20 - 9 min
This is all very interesting. When the CPU is at 100%, it’s likely running the denoiser. When Reference Motion Blur is disabled it will denoise every temporal sample with can make the issue worse. In 5.5 the denoiser runs on the GPU which should help.
The memory bandwidth between the 2 cards is probably playing a large part in the speed increase.
I could be faulty in my reasoning, but I would also like to further clarify the parameters of the project.
Materials - Substrate, there are different scenes, somewhere to optimize I remove skylight, direction light, skyatmosphere and the most surprising thing is that it gives a small performance, about 20-30 seconds, it could seem like a margin of error, but I did 3 tests and it’s a pattern. Given that I remove them in scenes where they are not visible (interior and emphasis on a small thing conditionally lamp).
Additionally I have studied other things, denoizer based on your message works only on one core of the CPU, in my case it is the 8th core by count, lacks support for multithreading, but if you will implement fully on the GPU it will cease to make sense. And in groomed frames, the increase in video memory (3090ti vs 4070 super) results in the 3090ti rendering a frame in 9 minutes on 5.4.3 and 13 minutes 30 seconds on 5.3.2, while the 4070 super has the same render time in 5.3.2 and 5.4.3 - 49 minutes 24 seconds per frame. Disabling the translucent network in a scene where there are transparent windows through which direction light shines in the volumetric fog results in an increase in render speed from 4 minutes per frame to 3 minutes and 40 seconds.
I would ask or maybe initiate an addition to your existing documentation on Path Tracing, and specify in it what exactly affects the speed of performance
Also I create a test scene with configurable parameters and want to share with you for more information from up message. Thank for you furure answer! I wish in perfect future of PT in UE
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.