Identical to the Cyrix PR166+ except for the branding. Cyrix is the designer of the M1R-core but didn't have manufacturing plants for their chips so they initially out-sourced it to SGS Thomson (for the 90+ and 120+ models). Eventually they switched over to IBM's manufacturing plants.

Apparently SGS Thomson stayed in the picture as they brought the later Cyrix' M1R-chips (manufactured by IBM) to the market with a SGS Thomson branding. > Read more

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This CPU uses the same core as the IBM 6x86. If you wonder why: read here . > Read more

Identical to the IBM 6x86 P200+ but with a lower core clockfrequency and front-side-bus. > Read more

Consider first: 440nm, only 3,3M transistors, 150MHz and 3,5V. In other words: older manufacturing technology, same amount of transistors compared to the Pentium, Pentium topped out at 100MHz with 600nm; this goes up to 150MHz and powered at 3,5V is heat guaranteed! Although it's just a few watts extra heat dissipation; back in the day most system integrators didn't care that much for cooling. A generic small socket 5/7 heatsink/fan was provided but in hot-environments they weren't the best choice for the P200+. However, the Cyrix chip can handle heat very well so I doubt they really suffered from it.

Specs-wise it needs a good design in order to keep up with the other competing brands. Luckily, for Cyrix, they had this CPU available in June 1996 which is somewhere around the release date of the Pentium 200. See the benchmarks and look what Cyrix had to offer back then. In short summary: FPU performance is bad so you can't play Quake very well but integer performance is excellent and because of that Dhrystone is almost as fast as a Pentium 166! Also take a look at Doom (which doesn't use the FPU); it's ahead on the AMD K6-166 and nearly as fast as the Pentium MMX 166 and Pentium 200.

I remember this CPU running Quake and Half-life very slow (no wonder with that kind of FPU!) but Grand Theft Auto went really fast. Unfortunatly I have no way of benchmarking Grand Theft Auto but in my memory the Cyrix would outperform a Pentium MMX 200 if they both were fitted with a Voodoo Graphics card .

You might wonder why I mentioned Cyrix: this is because Cyrix designed the chip and IBM manufactured it. > Read more