This is fantastic.

I'm lucky enough to own a 17" MacBook Pro - and it's very interesting that I can use both GPUs at once (9400M as renderer and 9600M as compute engine), as I didn't think this would be possible.

9600M = 46 GFLOPS
9400M = 21 GFLOPS
Hybrid = 25 GFLOPS

Given the speed of calculations, it looks like hybrid CPU+GPU must be using 9400M for GPU compute (or hybrid is not nearly as efficient). It would be a great addition if the benchmark gave two hybrid options (one for each GPU), or identified which GPU it was using.

On another note, do you think it's possible to make Galaxies use multiple GPUs for compute? I realise that this is a big ask - as you've already indicated that the 9400M GPU can only process 4K elements...

Keep up the good work!