The AMD K5, a much underrated chip

AMD have come a long way from this, and yet this was the beginning of innovation over emulation from the California based Processor manufacturer. This was their first fully self-developed x86 CPU and it is a truly a remarkable one.

While all previous AMD x86 CPUs used Intel microcode and therefore could be considered 'clones', this one was completely different. Instead of natively processing the code, the K5 did an interesting pre-translation to a RISC-like code, like NexGen chips did before and all current x86 chips I know of do today. This took AMD years to develop so that the first K5 chips joined the processor war late, compared to Cyrix and Intel counterparts.

When those K5 chips finally arrived in early 1996, both Cyrix and Intel already had their 200MHz/PR200 parts out, but with its 75MHz and 90MHz parts AMD was hopelessly out-paced. In addition, the early 'SSA5' versions were still running sub-optimally - you might want to call them a working 'pre-release' K5.

In May 1996, AMD switched to the K5 label instead of 5k86 (no-one would remember that, would they!). So this K5-PR133 is a chip running at 100MHz and was produced in late 1996 and performed (according to AMD) as fast as a Pentium 133MHz.

Like the Intel Pentium, the K5 was a superscalar design meaning that it had more than one execution unit per processor. This allowed it too to make the quantum leap in performance over the 486 which was common with 5th generation designs. It too was also pin compatible with the then prevailing Socket 5 and 7 motherboard connectors. This allowed it to run in the same motherboards as the Pentium itself.