Cyrix entered the fifth generation processor market with the 6x86 processor, formerly projected as the M1. As a successful and cheaper (often less than half the cost) alternative to the Intel Pentium, it is pin- and voltage- compatible with it. Cyrix gave it the 6x86 name in reference to some of its more advanced features, which it calls "sixth generation". In reality, the processor is comparable in power and architecture to the fifth-generation Pentium.
The MX went from PR166 to PR433, an impressive spread. In the course of its life it went from 0.35u to 0.18u and 2.9V to 2.2V. The name was later changed from 6x86MX to MII to compete with the Intel Pentium II.
As a fabless company Cyrix had other companies produce their chips, often part of the agreement was that these foundries could sell their own version of the chip. (such as IBM and National)
The 6x86MX and MII are closely based on the 6x86 with a few additions: MMX Support Support for more multipliers L1 Cache increased to 64K (from 16K) Doubled the Branch prediction. (to 512 entries) 32-bit optimizations 256 bytes Intruction cache (pre-L1 cache) ----------------------------------------- The Cyrix MX design was used by: IBM National Semiconductor -------------------------- Actual Speed: 166 Bus Speed: 66 Multiplier: 2.5 Fab'd By: IBM ----------------------------