Sated Devourer causing fps loss.
Spectating a few games earlier were running steady at ~30-40 fps. When Sated Devourer kicks in, the framerate drops to 15-20, even if the Champion is alone fighting a single monster like a Gromp. Prior to the purple "echo" showing up at Sated, there was no discernible fps loss in a similar situation.
The one the framerate most most noticeable was on a Jax jungler, but similar fps slowdown was present on Yi, Shyvana and Vi. The little dog did not decrease fps.