Certain parts of PhysX are threaded quite well, but to get the most parallelism you need to use the ‘async scene’ and accept that those objects will be a ‘frame behind’. Also note that lots of physics objects can often mean lots of dynamic components, which can have their own cost rendering-wise. It’s worth using the stats system to work out what is going on. We are constantly talking with NVIDIA about improving performance, and there should be more improvements coming down the pipe in future versions of PhysX (3.4 and beyond).