At the heart of the processor is what interim CEO Steve Jobs dubbed the 128-bit Velocity Engine, which presumably refers to the AltiVec instruction set drafted by Motorola Inc. But whether the G4 is being fabbed by Motorola, IBM, or both was not immediately clear. Apple's literature only refers to the G4 as being "architected by Apple, Motorola and IBM."

In any event, Apple is pushing speed as a selling point for G4-based Macintoshes. Apple claims the Velocity Engine gives the G4 a sustainable performance of 1 gigaflop and peak performance of 4 gigaflops. Apple claims to have data from Intel Corp. showing the 500 MHz G4 runs more than twice as fast as a 600 MHz Pentium III.

The first desktop machine to use the 500 MHz G4 will be a Power Macintosh priced at $3,499. Apple also announced slower G4 Power Macs priced at $2,499 and $1,599. Servers using the G4 are due to be available in November.