Here are 2 files one should fit in an 8GB GPU and the other in a 12GB GPU
For the 12 GB I used a:
Titan X with 12 GB and simmed in 14 m 48 secs
For the 8GB scene
1070 8GB simmed in 5 m 53
Titan X 12GB simmed in 7m 1 sec
Though the Titan has more cores and more mem the 1070 has a higher core and mem clock rate.
Some one on the cafe tried the 12GB scene on a 2080-Ti 11GB GPU and simmed in 6m 5 secs which is more than 2x faster than the Titan X
Though not a render test he got frame 75 of the larger file to render in 3 m 41 secs and I got 6m 31 where 5m 30 of that was preparing geometry. Using the 1070 and the Titan X.
Converting to vdb i get the frame to render in 30 seconds !!
As this is not a render test leave the C4D light on when rendering in redshift, I know it should not be on but i forgot to turn it of and the cafe chap tested with the scene as is so i am basing my times on an as is file. 8g.c4d (342.1 KB) 12g.c4d (315.1 KB)