We’re seeing some abnormal performance behavior when running an OpenMPI 1.4.4 application on RH6.4 using Mellanox OFED 1.5.3.  Under certain circumstances, system CPU starts dominating and performance tails off severely.  This behavior does not happen with the same job run with TCP.  Is there a resource that shows what’s compatible with what?  For example, does OpenMPI need to be rebuilt when an OFED changes, etc?