There also this from DSOG if anyone is interested:
What/where is the specs of the pc tested with the multiple gpus. This benchmark isnt very helpful."Total War has traditionally been quite CPU-bound, with the game-draw and graphics render processes both running on the same CPU thread." wrote Creative Assembly in a new post and continued.
"Over time, as the engine has evolved and become more demanding, this has become an increasingly important bottleneck for us. During the course of TWWH's development, we've spent time separating these so they now run independently on their own threads. We've also optimized our task-system to have better multi-threading performance across the board."