The original Apple Power Mac G4, code name "Yikes!", was introduced at the Seybold conference in San Francisco on August 31, 1999, with 400 MHz, 450 MHz and 500 MHzconfigurations available. In October 1999, Apple was forced to postpone the 500 MHzbecause of poor yield of the 500 MHz chips. In response, Apple “speed dumped” the processor speed in each configuration by 50 MHz but caused some controversy by not decreasing the price of the machines.
The early 400 MHz (later 350 MHz) PCI-based version used a motherboard identical to the one used in Power Macintosh G3 (Blue & White) computers (minus the ADB port), in a "graphite" colored case and with the new Motorola PowerPC 7400 (G4) CPU. The higher-speed models, code name "Sawtooth", used a greatly modified motherboard design with AGP2x graphics (replacing the 66 MHz PCI slot). In December 1999, the entire Power Mac G4 line was updated to the AGP motherboard.