But to give you an idea of the speed. This is what it looks like after 20secs.
This image is 1920x1080 using direct lighting algorithm. Render time = 1min30secs.
Octane Render is very new GPU based interactive unbiased renderer from Refractive Software. It is currently in an open beta testing phase in which you can join for a discounted price (currently 99 euros). Not only do you get early access to all versions but you are also licensed to use all final v1.x point release versions.
I'm currently testing my own copy atm. I will post a review here later in the year when it is close to or soon after release.
