XFdtd is a full wave electromagnetic solver based on the Finite Difference Time Domain method. It is fully three-dimensional. Complicated CAD objects with thousands of parts may be imported into XFdtd and combined and edited within XFdtd using the internal graphical editor. RF designers can import an electromechanical CAD file, improve the design using XFdtd, then export the revised CAD file to reduce design time. Applications include microwave, RF, antennas, scattering, biological EM including MRI and SAR, photonics, packaging, EMC, and electromagnetic behavior of specialized materials. XFdtd offers many important and unique capabilities including Fast Meshing Algorithm, mesh preview before calculation, a wide variety of complex electric and magnetic materials including nonlinear and frequency-dependent, nonlinear device modeling including both diodes and capacitors, anisotropic materials, and many others. XFdtd is the only commercial time domain solver with true MPI capability which allows large problems to utilize the full capability of computer clusters. XFdtd supports XStream hardware FDTD for extremely fast calculations using the graphics processing units in high speed video cards. No other EM software can solve larger problems or solve them faster than XFdtd.