Following the K6, AMD launched the K6-2 one year after the first introduction of the K6 166 MHz. First version launched were clocked at 266, 300 and 333 MHz, then 350 MHz and more. They supported MMX and the new AMD's 3DNow! instructions set. This engineering sample was clocked at 66 MHz with a clock ratio of 6.5x. No date code on this sample, but the commercial K6-2 433 MHz was announced on September, 20th 1999