Thanks to the support on the hardware for Octane group on Facebook, I have now a good working system with a AMD Ryzen 7 5800X, MSI Geforce RTX 3070 Gaming Trio 8Gb, and 64 Corsair Vengeance DDR4-3200.
Trying to open up old files from my old pc system (Nvidia980 Ti Hybrid card, 32 GB ram, with C4D R20, Octane V4 plugin), and most of the old files look the same as before when rendering, but one file is acting weird. Now running C4D R21.115 with Octane plugin 2020.2.3-R3, and Nvidia Studio Driver 462.31. Mostly I render with pathtracing and in one specific file nothing appears in pathtracing mode, only some added headlights on a car are visible, everything else is black. when I change to Directlighting I can see the rest of the image with textures etc.. without a problem.
Don't know what the problem is, but if this was not a problem to render this file in my old system without any errors, it should be something with my settings in C4D or the plugin or the driver. Does anyone have some advice on this?