Cebas has updated their fluid, rigid body and particle F/X simulation framework, knows as thinkingParticles to version R4.

In addition to other changes and enhancements, existing PhysX SDK integration is now using 64-bit PhysX solver.

Moreover, it seems now Cebas is more focused on their own rigid body solver called ShapeCollision 2:

The new ShapeCollision operator incorporates, for the first time ever, true Multi-Core (CPU) support for most parts of its collision detection and overall solving. The accuracy of the solver has been enhanced beyond belief and the stability that you derive is unmatched by the old ShapeCollision or any PhysX simulation.

Speed is always an issue in complex physics simulations, PhysX delivers already fast game quality physics but it is not good enough for the Hollywood style of effects, which need way more accuracy than PhysX can deliver. Thanks to a much more enhanced multi-core (CPU) support that SC has to offer, the simulation times can be reduced by a factor, as much as, 10 times when compared to the good old ShapeCollision!

However, it seems good grain of salt is needed here