Decreasing GPU frequency by 150 MHz helped. Thanks!!!

Does malfunctioned gpu work fine alone?

Nope, it is the one that crashes Octane renderer / Cinema 4D when Octane is activated.

Nothing extreme or suspicious in the log. You may have problems with OS/driver/gpu.

Thank you.

* I tried clean driver install as suggested here https://render.otoy.com/forum/viewtopic.php?f=86&t=70253 but it didn't help.
* So I tried to turn off one of the two cards in Octane settings and try to ...

Here is the Cinema 4D log:

Loaded Octane DLL:OctaneRender Studio 4.00 version:4000021
Octane Render VR for Cinema 4D V4.00 built for:190 C4D vers:19068
Octane Render SDK version: 4.00
Py-Parametric Tools 1.0 successfully initialized
Activation time=5.109 sec.

FRAME 54 fps:30 ...

I have just tried Octane 4.01.1 RC2 and it is exactly the same. When I try to render the scene to PV Cinema 4D gets frozen for a second and it crashes without any errors. Or maybe there are some error C4D error logs but I don't know where to look for them.

Thanks

A. Windows 10
B. 2x Zotac 1080 AMP Extreme
C. 64 GB DDR4
D. Nvidia driver version 417.35
E. /
F. OctaneRender plugin version 4.0
G. Cinema 4D R19.068 Studio
H. I get random octane errors. The last one (see attached log) happened while I was rotating the camera.
I. Copies of the Octane Log window ...