FWIW, here's my 2 cents..
I have a Win 10 system I purchased last year from CyberPowerPC
It has an Intel i7-6800K CPU @ 3.40GHz
32 GB RAM
I have a GeForce GTX 1080 (foundation version) and a GeForce GTX 980Ti both installed.
Frankly, you only need one unless you're doing hi-end rendering with programs like Octane.
I purchased the 1080 for a number of reasons:
1. I want to do VR and it's probably the best performance/value for hi-end VR like Occulus and HTC Vive (I use it with both)
2. I also want to use it for non-biased photoreal rendering with products like Octane. The 1080 performs very well, and coupled with the 980Ti, the two perform very nicely.
3. Pascal is the 'latest-greatest' and I expect buying now at the early stage extends the life of this architecture.
4. Because it's such a standard, I also expect future programs to continue to optimize for the 1080 and future Pascal architectures.
5. I prefer the "leading edge" not the "bleeding edge." I don't want to have to research, debug, install beta drivers, etc. in order to use a device. Certainly there are faster and more expensive cards / rigs out there, but then you get in the game of continually having to know which device works with which setup, etc.. I just don't have time for that.
6. Unity (and UE4) have both announced support for Octane to bake textures. As I've mentioned previously, if you *learn* Unity, you can create stunning renders (like KeyShot and/or Octane) plus 8K animations in near real-time (based on the 1080 board). I can render individual 4K images in the time it takes me to move the camera view-- just press the snapshot button and it saves a 4K image to disk. Just amazing. And when Octane (announced it will be FREE for Unity) comes out later this summer, it will be a game changer as far as realtime rendering goes. Check this out!
https://youtu.be/8ecfZF-IuSI?t=2m25s
I'm very happy with my decision and my rig has performed extremely well. Purchasing an industry standard hi-end gaming video board is, IMO, the way to go if you're focussed on rendering. If for only CAD and 3D printing, it's not necessary.
