Corona is not using 100% of CPU

[CeBeP]

I had 16 Gb RAM, so HDD was used for 100% while rendering, and CPU for 3-15% (yes, i had error message about "not enough RAM"). So i put 32 Gb RAM in it, now i have some empty error message, and still HDD=100%, RAM = 77%, CPU = 14% after few hours of rendering. What can it be? Am i alone with this problem?

[PROH]

Hi. Regarding low CPU usage I just had a similar experience. Suddenly my CPU dropped to 13 - 20%, and "ray pr sec" dropped dramatically to. After some search I found out that it was caused by a material with a tiled gradient ramp in the bump slot. If I turned off "tile" or removed the map the CPU vent back to 100%, and the "ray pr sec" raised to normal level.

Do you use a tiled gradient ramp in one of your materials? If so, what happens if you remove it?

[romullus]

Hi. Regarding low CPU usage I just had a similar experience. Suddenly my CPU dropped to 13 - 20%, and "ray pr sec" dropped dramatically to. After some search I found out that it was caused by a material with a tiled gradient ramp in the bump slot. If I turned off "tile" or removed the map the CPU vent back to 100%, and the "ray pr sec" raised to normal level.

Do you use a tiled gradient ramp in one of your materials? If so, what happens if you remove it?

If you can reproduce such behaviour, please do report it as a bug. I use gradient ramp as a bump map quite often - haven't seen any issues so far.

[PROH]

It was my plan to report it. I just haven't had the time to test it once more yet. But I hope I can do so tomorrow.

BTW - the gradient tiling was set to "use world scale", and it happened with daily build 12-03-2016.

[Ondra]

were you using DR?

[PROH]

In my case no, I was not using DR.

BTW I didn't get the time to do a deep re-test, but I did make a quick try to see if I could reproduce it on another PC (my home PC - i7), and that I could. Only difference was that the drop wasn't as big as on my work PC (2x Xeon E5 v3).

Will see if I can get some time to post an example.

[Ondra]

It could be caused by some of the maps. Can you try it with gray material override? Or just send us a scene where it happens

[Ondra]

Hi,
any progress? You could also try creating minidump of live application (see #2) - we may see the cause of the problem from there https://coronarenderer.freshdesk.com/support/solutions/articles/5000524006

[guilin]

When I use corona it only uses 85% of cpu. Why is that so?

(incorrect screenshot removed)