Computer chip maker Advanced Micro Devices on Monday unveiled the first PC Processor running at a so-called ``clock speed'' of one gigahertz, beating its far larger rival Intel Corp. in achieving a long-sought milestone in the PC industry.

Chip makers have long regarded the one-gigahertz threshold as a sort of Holy Grail in performance -- even though few PC users actually require such ultra-fast speeds. For more than 20 years, personal computer processors have measured their clock rate -- the raw measure of internal speed -- in millions of cycles per second. AMD said it began shipments of its AMD Athlon processors running at one gigahertz, or one billion clock cycles per second, an announcement that had been widely anticipated. Previously, AMD_s fastest processor was an 850-megahertz Athlon chip. Compaq Computer Corp. and Gateway Inc will begin taking orders for PCs equipped with the new chips within days. ``Achieving production of the gigahertz processor is the chip industry_s equivalent of breaking the sound barrier,'' Steve Lapinski, director of product marketing in Sunnyvale, Calif.-based AMD's computation products group, said on a conference call with reporters.