TITAN vs 2 x GTX1080

Hi !
Dear Video Motion Artists and Inventors.
Please help me to find solution for my Workstation.
What will be more powerful and more effective for AE and GPU rendering (Like iRay or Octane and similar)

1x Nvidia TITAN 2016 or 2x Nvidia GTX 1080 in SLI mode ?

Many Thanks for your opinions !

(Now Im using quadro k5000 but its epic fail)

AE doesn’t really use the GPU a lot, although more and more effects are GPU enabled, I still see AE as a CPU demanding software. Only Element 3D makes really use of the GPU.

The main difference between 1x Titan or 2x 1080s would be the amount of VRAM being more on the Titan with 12GB vs 8GB on the 1080. So you can handle bigger scenes with the Titan in 3D Renderings.

Speedwise, 2x 1080 should be a lot faster as long as the GPU renderer is able to make use of several GPUs.

Octane can handle multiple GPUs well, as far as I remember, and if the same is true for iRay then I’d always go for 2x 1080s. Don’t use them in SLI, use them as seperate GPUs.

I heard Element can’t use multiple GPUs for rendering. I could be wrong. But if that is the case, then it’s likely that some other effects might only use one GPU as well. I’d go for the one Titan.

Many Thanks ! It’s really useful information !
As I understand AE can use multyply GPUs and will speed up OpenCL stuff like the Ray-Trace Shadows and Ambient Occlusion in Element 3d. Element 3D unfortunatly dont use more than 1 GPU for OpenGL rendering. Maby in the next versions they fix this problem.
But I didnt understand about memory. 2x1080 its 2x8GB - 16 GB its more than 12GB in Titan. Or memory is not summed up?
Also in 2x1080 more Cuda cores (around 5000) and Titan have just 3500. I think for GPU renders it is much better.