Additionally, the 7400 has enhanced support for symmetric multiprocessing (SMP) thanks to an improved cache coherency protocol (MERSI) and a 64-bit floating point unit (FPU), derived in part from the 604 series.
The PowerPC G4 family supports two bus technologies, the older 60x bus which it shares with the PowerPC 600 and PowerPC 7xx families, and the more advanced MPX bus.