fvlib is essentially a minimalistic 3D point-spring solver library, built with high-performance in mind. It uses Verlet Integration for the calculation of point trajectories and Dynamic Relaxation for the calculation of constraints.

fvlib release 2 adds support for parallel processing of points and links, via the java.util.concurrent framework. It offers an increase in performance of about 50% from the previous release, given a dual core computer.

Read more about it in my blog!
http://prototy.blogspot.com

Also, if you end up in using it in a computer with more than two cores/processors, I would appreciate it very much if you could publish your figures from running the test app here or on my blog, just to see if there is actually a performance increase resulting from the use of more than two threads.
Just for reference I mention that the default set of the test application produces a figure of 15-16 msec (previous version was 22-23 msec).

Thanks!

EDIT: Link to download was initially broken, is ok now