Editing Cyrix (section)

=== Cyrix 6x86 ===

Later in 1995, Cyrix released its best-known chip, the [[Cyrix 6x86]] (M1). This processor continued the Cyrix tradition of making faster replacements for Intel designed sockets. However, the 6x86 was the star performer in the range, giving a claimed performance boost over the Intel "equivalent". 6x86 processors were given names such as P166+ indicating a performance better than a Pentium 166&nbsp;MHz processor. In fact, the 6x86 processor was clocked at a significantly lower speed than the Pentium counterpart it outperformed. Initially, Cyrix tried to charge a premium for the Cyrix-claimed extra performance, but the 6x86's math coprocessor was not as fast as that in the Intel [[Intel P5|Pentium]]. The main difference was not one of actual computing performance on the coprocessor, but a lack of instruction pipelining. Due to the increasing popularity of first-person 3D games, Cyrix was forced to lower its prices. While the 6x86 quickly gained a following among computer enthusiasts and independent computer shops, unlike AMD, its chips had yet to be used by a major OEM customer. The game in question causing most problems for performance was [[Id Software]]'s ''[[Quake (video game)|Quake]]''. Unlike previous 3D games, ''Quake'' used the pipelined Pentium FPU to do [[Texture mapping#Perspective correctness|perspective correction]] calculations in the background while [[texture mapping]], effectively doing two tasks at once. This would not have been a big problem for the 6x86 if, by that time, ''Quake'' had a fallback to do perspective correction without the FPU as in, for example, the game ''[[Descent (1995 video game)|Descent]]''. However, id Software chose not to include this. ''Quake'' also lacked the option to disable perspective correction, thus eliminating that potential speed boost for FPU-weak CPUs. This potential speed boost would have benefited not just Cyrix's users, but also users of AMD's K5 and especially of the 486. ''Quake''{{-'}}s optimization for the Pentium went beyond FPU usage and catered to a number of other architectural quirks specific to the Pentium, further hindering performance of other CPUs even outside FPU operations. This bias in favor of the Pentium served to boost the popularity of Intel's Pentium CPUs amongst the computer game community.