This could be windows reporting the usage wrong or in your power management, cpu usage is set to 90% instead of 100% or there can be some other causes as well. You can test with 3ds Max default renderers like arnold and scanline if using those your task manager reports 100% usage, we can investigate further.
thanks i will do some tests, once i’m done with work.
i checked with scanline - also aroun 90% usage.
Then i checked the power-management settings… its set to 100%.
But maybe the reporting is wrong - not sure where to set it. But then it does get to 100% occasionally.
Also checked the cpu-temperatures but its staying below 80°C so that probably wouldn’t be the reason as well.
If the behavior is consistent with another renderer as well. It could be just windows reporting wrong usage sometimes. Maybe check if your windows is missing some important updates.
its all UpToDate unfortunately
The “CPU usage” is not that simple. Please check this (very old) post: https://forum.corona-renderer.com/ CPU FAQ
This part is especially important:
How is it possible that there is code being executed 100% of the time and the CPU is not fully utilized?
Modern CPUs have many execution units specialized for different tasks. Most applications are able to utilize only some portion of these units at any given time. For example MS Word doesn’t need to do much floating point calculations, so the floating point execution units just sit idle when the CPU is running Word.Even if the application was able to keep all the execution units fully utilized, it may not be able to feed them with data fast enough. Modern CPUs are a few orders of magnitude faster than modern RAM, so when the CPU is able to process the data faster than the memory is able to supply it, the CPU will end up waiting for the data most of the time.
Same here, cpu-usage around 90%.
Processor AMD Ryzen 9 5950X 16-Core Processor (3.40 GHz)
RAM 64,0 GB
windows 11 x64 updated
Corona 14
HI,
Can you also try what I said earlier?
Do a quick test with Arnold or Scanline and see if Task Manager still shows around 90% CPU.
If yes, it’s likely just Windows showing it wrong or some power setting thing.
Like Marcin share above, modern CPUs have many parts doing different jobs and are much faster than RAM, so they sometimes wait for data that’s why you might see 90% even when it’s fully working.
It is 100% reporting issue. Thanks for your tests 
