Hi Marco,

for supplementary information you can see the Octane FAQ as well:

https://home.otoy.com/render/octane-render/faqs/

there is written:

OctaneRender requires a CUDA enabled NVIDIA video card. An up to date list can be found here ( https://developer.nvidia.com/cuda-gpus ).

OctaneRender can run on most CUDA enabled consumer video cards, instead of only on high-end Quadro cards that most other solutions and middleware require, but it is specifically optimized to run on Kepler (GTX 6xx, GTX 7xx, GTX Titan), Fermi (GTX 4xx, GTX 5xx) and Maxwell GPUs.

Kepler GPUs allow a higher texture limit (256 compared to 128 on Fermi) and are more power efficient and silent than Fermi cards. GPUs from the GeForce line are usually higher clocked and render faster than the more expensive Quadro and Tesla GPUs.

The GeForce GTX 780 and GTX Titan currently offer the best performance to price ratio, but any recent high end NVIDIA card will offer great rendering performance with Octane.

As Octane does not use the CPU for rendering, an expensive multi-core CPU is not required. However, a fast multi-core CPU will significantly improve the scene loading speed.

... this link ( https://render.otoy.com/octanebench/results.php?sort_by=avg&filter=gtx%20750&singleGPU=1 ) can be useful for you too.

Ciao
Mik