@ lancemoody - yes, this is exactly what happened to us and the same exact behavior and crashes. we have been working on this all day yesterday and this morning, until for some reason we noticed that all of the sudden C4D worked fine and didn't crash. I was pounding on it and pushing heavy scenes all around the viewport, trying as hard as possible to make it crash. But it was all of the sudden super stable. I didn't understand what was going on, until i noticed that the office was so quiet
I looked at the temp indicator and all gpu's were at 86 degrees - then it dawned to me - after the last crash and reboot i forgot to fire up MSI afterburner, which we have always running in oder to control fan speed of all 4 gpu's. Sure enough i fired it up to see what would happen and within 1 minute i had the same exact crash. rebooted again, didn't start up afterburner and fired up an animation sequence that would never render past frame 16 and voila - it went all the way to the end.
Not sure if that will apply to everyone, but for our case this seems to totally fix the problem and C4D with latest octane version works once again very stable. Now, the only thing to figure out is, how to control fan speed without the afterburner app.
Thanks for everyones help.