Discontinued processors

8086, Am286, Am386, Am486, Am5x86

Main articles: Am286, Am386, Am486, and Am5x86

In February 1982, AMD signed a contract with Intel, becoming a licensed second-source manufacturer of 8086 and 8088 processors. IBM wanted to use the Intel 8088 in its IBM PC, but IBM's policy at the time was to require at least two sources for its chips. AMD later produced the Am286 under the same arrangement, but Intel canceled the agreement in 1986 and refused to convey technical details of the i386 part.

AMD challenged Intel's decision to cancel the agreement and won in arbitration, but Intel disputed this decision. A long legal dispute followed, ending in 1994 when the Supreme Court of California sided with AMD. Subsequent legal disputes centered on whether AMD had legal rights to use derivatives of Intel's microcode. In the face of uncertainty, AMD was forced to develop "clean room" versions of Intel code.

In 1991, AMD released the Am386, its clone of the Intel 386 processor. It took less than a year for the company to sell a million units. Later, the Am486 was used by a number of large OEMs, including Compaq, and proved popular. Another Am486-based product, the Am5x86, continued AMD's success as a low-price alternative. However, as product cycles shortened in the PC industry, the process of reverse engineering Intel's products became an ever less viable strategy for AMD.

K5, K6, Athlon (K7)

Main articles: AMD K5, AMD K6, and Athlon

AMD's first completely in-house x86 processor was the K5 which was launched in 1996.^[7] The "K" was a reference to "Kryptonite", which from comic book lore, was the only substance that could harm Superman, with a clear reference to Intel, which dominated in the market at the time, as "Superman".^[8]

In 1996, AMD purchased NexGen specifically for the rights to their Nx series of x86-compatible processors. AMD gave the NexGen design team their own building, left them alone, and gave them time and money to rework the Nx686. The result was the K6 processor, introduced in 1997.

The K7 was AMD's seventh generation x86 processor, making its debut on June 23, 1999, under the brand name Athlon. On October 9, 2001 the Athlon XP was released, followed by the Athlon XP with 512KB L2 Cache on February 10, 2003.^[9]