The processor in the Power Mac G4 computer is a PowerPC G4 microprocessor running at a clock frequency of 350, 400, or 450 MHz. The PowerPC G4 microprocessor uses a new pipelined system bus that is more efficient than the system bus on the PowerPC G3 microprocessors. The new bus design, called MaxBus, allows for much greater efficiency of bus utilization than was possible with the previous design.
Features of the PowerPC G4 include:
32-bit PowerPC implementation
superscalar PowerPC core
AltiVec technology: 128-bit-wide vector execution unit
dual 32 KB instruction and data caches (the same as PowerPC G3)
support for up to 2 MB backside L2 cache
on-chip L2 tag storage (twice as much as PowerPC G3)
high bandwidth MaxBus (also compatible with 60x bus)