I don't like to post here unless a render is involved, sooo...
Sexy Dee of Whorg (again...)
On the rendering back and forth, I'm guessing that
Big Rooster is using a rendering mode other than Iray, based on the last few series of pics. They could be done in Iray with some post work afterwords, but that doesn't look like Iray to me.
3Delight, Filament and Open GL won't get much use out of any GPU, as they are CPU based rendering engines. Iray works best with Nvidia GPUs sure, but in some cases, depending on the 'style' you are going for, other CPU based rendering engines can be just as fast (maybe faster depending on the scene, also higher core counts help a lot with CPU based rendering engines).
There are tradeoffs of course. I prefer the Iray 'look' myself, but some do just fine with 3Delight, and of course there's the new Filament rendering engine.
As for the GTX 680 with 2GB of VRAM, that might be useful for displaying the desktop, freeing up the GTX 1070 completely for rendering and Iray viewport modes, but unless it's a VERY basic scene it might not be very helpful for Iray rendering. Plus I'm sure that if
Big Rooster does any significant gaming on his system, the 1070 would be the better choice for that!
I do encourage people to find their own styles. A particular style may not agree with me, but if we all rendered and did post work the same way around here, this thread would get rather boring rather quickly. The choice of rendering engine can have a huge effect on a person's 'style' and you shouldn't feel like you HAVE to use Nvidia Iray just because a bunch of other people do. It's easier in some respects, but that doesn't mean that the other rendering engines are useless - far from it!
So I AM curious as to whether
Big Rooster is using the Nvidia Iray rendering engine, or another rendering engine, as it is very pertinent to the discussion being had. I'd encourage not letting this thread get off topic though, Programming and Development is a great place to have discussions about rendering hardware, and there are a few threads to that effect in that forum. Also, discussing this with each other via PM is also fine!