Been using Octane since 2010 for Poser scenes and it is awesome! But also limited.

Some important info I would like to share before people run out to buy new graphic cards to use with Octane!

Octane uses your graphic card for rendering - not the CPU! It must be a CUDA (Nivida) card. That also means it can only use the amount of RAM available on your graphic card. Just remember that your desktop use RAM and so does every program you run. So if you have a 1GB graphic card, you do not have 1GB available for rendering. It all depends on have much RAM your other running programs use. Just loading my Desktop and have Poser running will eat about 200-300MB leaving about 700MB for Octane to use. And that is not much for me. Octane will just show a black screen of you do not have enough RAM.

Another important thing is that the GTX500 series can only load 64 textures. The new GTX600 series can load 128 textures. It's a CUDA limtation problem. It would seem a GTX600 would be better. Well, yes and no.

The GTX500 series cuda cores are much stronger than on the GTX600 series. A GTX580 is in Octane faster than a GTX680 even though the GTX680 have 3 times more cuda cores. But on the other hand the GTX6xx can take twice the amount of textures than a GTX5xx. So I will leave up to you what is best for you.
http://render.otoy.com/forum/viewtopic.php?f=25&t=23225

If we take Stonemason's Courtyard prop. That scene has over 100 textures. So it will not load every texture on a GTX5xx card but it will on a GTX6xx. But adding a figure with clothes might get over the 128 textures anyway. You see the problem?

Just remember you're limited to what the craphic card can offer you. But there are workarounds but some of them are not easy to do.

Normally a figure texture is about 4096x4096 in pixel size. Octane will convert the textures to RGB and that takes up some RAM. If you reduce the texture size it will also lower the amount of ram used. And that can really help alot to fit big scenes into the RAM on the GFX card.

I also noticed some hair products can use 10 textures just for the hair. That's alot! Might be better to find a product that doesn't use that many textures to keep the texture count low. In some cases you can even reuse some textures for other objects and reusing textures will not count is an extra texture.