Cyrix III

The Cyrix III was a brand of x86-compatible central processing units (CPUs) developed by VIA Technologies after their acquisition of Cyrix in 1999. It represented VIA's attempt to compete in the budget and low-power CPU market. Two distinct microarchitectures were marketed under the Cyrix III name, causing considerable confusion: the Jalapeno core and the Samuel 2 core.

The initial Cyrix III, based on the Jalapeno core, was essentially a re-branded and slightly updated Cyrix MII, which was itself derived from the Cyrix 6x86MX. The Jalapeno design inherited the MII's strengths, such as good integer performance, but also its weaknesses, including poor floating-point performance and inefficient branch prediction. It was hampered by its aging design and struggled to compete effectively against more modern CPUs from Intel and AMD.

VIA later transitioned the Cyrix III brand to a completely different core, the Samuel 2. The Samuel 2 core was originally designed by Centaur Technology, a company VIA had also acquired. This core offered significant improvements over the Jalapeno, including enhanced floating-point performance and improved branch prediction. While not a high-performance CPU, the Samuel 2-based Cyrix III was generally considered a competitive offering in the budget segment, offering a reasonable balance of performance and power consumption.

Due to the use of two completely different microarchitectures under the same name, "Cyrix III", benchmarking and product reviews from the era often need careful examination to determine which core was being tested. The Samuel 2-based Cyrix III models generally outperformed the Jalapeno-based versions. Eventually, VIA retired the Cyrix III name and rebranded their processors under the "VIA C3" name to avoid further confusion.