Yeah, but you need a standalone license for each slave machine. Max 12 GPUs.

Compute capabilities required for octane features:

from: http://home.otoy.com/render/octane-render/faqs/

Compute Capability Limitations
1.0 Octane Render Version 1.20+ not supported.
Version 1.1 or lower: No PMC kernel or matte material (shadow capture)
1.1 -> 1.3 Version 1.21+ not supported ...

Use CPU memory is for out of core textures. So, If you've got a kepler GPU you can store max 144 textures on it, the rest will be sent to CPU memory if surpased. Memory limit is how much memory you want to allocate for textures.

I'd still really like to know why is octane using so much CPU mem on ...

I'm trying to understand which segments are actually getting loaded into CPU memory when rendering. EG:

I got a 6 million poly scene, with 2 large displacement maps, which takes about 5GB of CPU mem when I render in full HD and 2GB GPU mem. My question is, what's actually getting stored in CPU mem ...