I have the same problem but in the AE interface, during the play preveiw of my comps, or simply the lag from dragging timeline cursor to comp preview render
I have a simple infographics elements, 3d camera with many (not so many) 2d elements.

Using CUDA with a gtx 1080 win 10 with xeon e5-2620 2.1ghz 64gb ram…
Change little bit downgrade my monitor 4k to full HD ….
I have more problems with complex others scene, with big big textures and 3D obkects…
I have a little test with gtx 1080 vs my old quadro k4000 ….
The Quadro has the same performance but quadro has 766 cuda instead of 2560 of gtx….
I know gtx is not supported, but used at the same (I think) using the trick of cuda_supported_cards.txt
How do is possible?! any help please … and solutions…. ☹
thx