Hi team...
I just want to let you know about bug that I found in C4D R21... If this was not mentioned before, in the Octane material 'menu> editor>, texture preview size = when changing to some value, C4D crash down and completely sign out of my MAC User account... Hope this helps to fix for future ...

Octane Houdini:
My Hardware: iMac Pro, Vega 64, 10Core + Radeon 5700XT (eGPU)

Because there's no option to send you crash/issue report, I just wanna let you know my first experiences:
''+''
1. eGPU works as expected
2. Rendering on my system is fast and smooth

''-''
1. Octane IPR not work (only ...

Smooth and fast on iMac Pro /10Core /Vega 64, but unfortunately, approximately 2 times per day freezes whole MAC, which made hardreset. Without option to send you crash report
The Houdini plugin works, but only on Mplay window - no Octane IPR with it's advantages is allowed.