AMD K5 - AMD's first original microarchitecture. The K5 was based on the AMD Am29000 micro architecture with the addition of an x86 decoder. Although the design was similar in idea to a Pentium Pro, the actual performance was more like that of a Pentium.
AMD K6 - The K6 was not based on the K5 and was instead based on the Nx686 processor that was being designed by NexGen when that company was bought by AMD. The K6 was generally pin-compatible with the Intel Pentium (unlike NexGen's existing processors).
AMD K6-2 - An improved K6 with the addition of the 3DNow!SIMD instructions.
