The Apple G4 processor/Velocity Engine 500 MHz is an average of 2.94 times faster than the Pentium III 600MHz shown in several tests published by Intel to demonstrate Pentium's speed. These figures (and others) have been disputed with mixed results. The product was, at its relase time, technically classified as a supercomputer, as it delivers sustained performance of over 1 gigaflop. Theoretically, the architecture could sustain performance of over 5 gigaflops.

The systems are configured standard with a Rage video card, ATA/66 hard drives, USB, FireWire, and 1 MB backside L2 cache, and PC-100 SDRAM.

The G4 chip is manufactured through the cooperation of technology giants Motorola, Apple, and IBM. The two versions in production at the beginning of 2001 are the MPC7400 and the MPC7450.

Information gleaned from Apple Engineers based in Atlanta, GA

August 25, 2001
Since the original creation of this writeup, additional G4 processors and configurations have become available from Apple. Currently, the G4 is available at speeds up to 867 MHz. Given the constant improvements and expansion of processing technology, I will probably not provide further updates to this w/u. If you post a w/u with more up-to-date information than mine, /msg me and I'll modify or delete mine to complement yours.
Thank you to mr100percent who suggested I provide an update to this wu.

September 25, 2002
Thanks to mblasefor pointing out that current G4 processors rank as fast as 1.25 GHz.
Also, I might add that Apple has added a rack-mount server to their repertoire based upon the 1 GHz processor. The XServe isn't Apple's first foray into server computing, but it is its first serious entry into the rack market. I have recently installed one of the dual-processor models and two of the single-processor models, but have not run performance tests. The ambient temperature in the case and on the processor card floats around 87 degrees Fahrenheit running at 2-3% baseline CPU load.