Octane Render completely relies on the GPU for rendering performance and scales extremely well. If your motherboard can accept more than one video card, adding additional video cards will greatly improve Octane's rendering speed because Octane's performance scales perfectly with the number of GPUs (e.g. rendering with four GTX Titans will be 4x faster than using only 1 GTX Titan), without the need for SLI. The cards can be different models, allowing GPUs from two completely different architectures to be used in a machine with multiple PCI-E slots (such as a GTX 560 in the primary slot and a GTX 780 in the second).
I have this question:
Anyone using 2 cards (for example, 2 GTX 680s for Mac) in a MacPro 5,1 with a single monitor? . . . second card for additional GPU/CUDA processing only?