It doesn’t make sense that the CPU would just be idle while the gpu is rendering… seems to me that’s why the engine is multi-threaded in the first place. Instanced Static Meshes don’t have this problem…
It would be really nice if one of the devs at Epic could comment on this problem. I am working on other issues at the moment so it’s not as though I’m not preoccupied, but I’d be lying if I said I have many other ideas to pursue for solving this particular problem at the moment.