Cyrix CPUs
Cyrix
Cyrix Socket 5/7 CPU's tended to have good windows performance, but a bad FPU and most tended to get (very) hot. Also most Cyrix CPU's tend to be very poor overclockers.
486SLC/DLC
Hybrid design of 386 and 486. 386 bus compatible with 1kb internal cache and support for i486 instructions. The 486xLC is an original design that does not use any Intel microcode. Although originally intended for OEM use only, they often find their way into the hands of end-users as upgrades for older 386 systems. However, upgrades are not always successful as older motherboards often do not support hidden refresh or the extra control lines needed to maintain cache coherency. Therefore, it is usually recommended a 486xLC only be installed in motherboards with specific BIOS/chipset support. However, motherboards can often be modified by those with good skills. 486xLC chips were later sold as special upgrade editions (DRx2, DRu2) which either provided the extra circuitry integrated into the CPU core or by an included "dingus" that sat between the CPU and socket. 486xLC chips were sometimes sold under the labels of other manufacturers (such as TI), but they are all internally identical. TI eventually fell out of favour with Cyrix and produced unauthorized 8kb versions known as "Ti486SXL" and Ti486SXLC".
486S
A version of the 486DLC modified to use a real i486 bus. The main difference was they had 2kb of internal writeback cache (versus 1kb in the DLC and 8kb in a real i486). These chips did not include math coprocessors, but were available in a "dingus" that sat between the CPU and socket. 486S also ran at 4V, versus the standard 5V of Intel and AMD chips of the time. Performance was better than the DLC but slightly slower than a true i486SX.
486DX, DX2, DX4 =
5x86 (M1sc)
A scaled back version of the original 6x86 core that was compatible with the 486DX bus.
6x86
Cyrix's first Socket 7 CPU. This CPU is rather slow (particularly for playing games) and produces a lot of heat.
6x86L
Cyrix's attempt to fix the heat issues, though it was only moderately succesfull at doing so
6x86MX/MII
This is basically a 6x86L with MMX instructions and a larger cache. Later renamed to Cyrix MII, this was also Cyrix's last processor line for Socket 7. As these CPU's were clocked (slightly) higher, the heat problems re-emerged. The heat problems were only fixed when a 2.2v version of the MII was released.
The Cyrix Socket 7 CPU's are generally not recommended for use in a retro build as there are better alternatives available. The most notable exception to this rule are the 2.2v parts of the MII which runs a lot cooler and are even somewhat overclockable. One note is that Cyrix CPU's support Linear Burst, which may accellerate it's performance by as much as 10%, though Linear Burst was never made available on Intel chipsets.
