Combination of different video cards.

I have one 1080ti in my rig. Can I add 980ti to speed up the computation of depth maps?

Works just fine. Computation of depth maps is about 50% faster comparing both cards with single 1080ti (22mins vs 33mins - tested on project with 830 photos).

 

Rest of the rig:

TR1950x

128gb DDR4

M2 2TB