The Cyrix 6x86MX / MII in use

In use the Cyrix MII has been something of a mixture. Its excellent integer performance has allowed to to keep up with Intel and AMD to around the 300 MHz mark. Unfortunately its floating point performance was never a match for its Intel and AMD rivals. The MII could never really be used as an effective gaming chip on these grounds alone. Also the lack of its speed rising over 250 MHz has been a severe drawback to this chip as now it struggles to make the grade even as an entry level solution against the K6-2 and the Celeron.

The MII also used non standard bus speeds during its time, these being 75 MHz and 83 MHz. As these speeds were never supported by Intel, they were never implemented in an effective way on most motherboards. We are referring to here the fact that running these speeds meant that the PCI bus was overclocked by the 75 and 83 MHz bus speeds as it normally runs at half of the front side bus speed when operating at 66 MHz and one third at 100 MHz. This overclocking of the PCI often causes stability problems with many cards, especially display cards.

Compatibility was also a problem for the MII as many programs often refused to run or suffered stability problems under this chip. It must be said though that this problem is not as bad as it was as many software companies now design software to run on a variety of different processors. Heat output once again became a problem once the chip's clock speed rose to around the 250 MHz mark (PR300 & 333).

Performance is adequate, but not quite up to the levels set by Intel and AMD. We think that the problem here is mainly to do with the fact that Cyrix uses the P Rating and not the true clock speed of the MII for its rating.

Cyrix 6x86MX / MII, the verdict

Can we recommend the Cyrix 6x86MX / MII to PC buyers, well yes and no. To the used buyer we would recommend that you look at systems powered by the Intel Pentium MMX or AMD K6, they are better in our opinion. To the new buyer things are a little bit different. The Cyrix MII now is becoming a very cheap processor indeed, we have seen PR300 examples being sold for as little as £30, which is an absolute bargain in our opinion. If a buyer is looking at a PC system priced at around £700 we would advise buyers to look at either the Intel Celeron or AMD K6-2. It is in the newly emerging £400 to £500 PC market where the Cyrix MII is very strong. In these bargain priced PC's we think that the Cyrix MII is very good value indeed!

Cyrix 6x86/MII® Processor, Technical Data

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Other Cyrix Processors at:

• Cyrix 6x86/6x86+ page