Motherboard Help Pages

4.I have bought a Cyrix MII 300 and I have set the motherboard to 3x100 (100MHz bus and 3 times multiplication factor) but it won't run at all. What should I do to get it to run?

All Cyrix MII processors have their speed quoted as a benchmark comparison and not at the actual speed that the processor runs. The idea is basically that although it does not run at 300MHz it is on average as fast as an Intel Pentium 300. In practice most people find the Cyrix processors performance to be more in line with the actual processor speed rather than that of the quoted benchmark. However there are quoted benchmarks that do support the supposed higher figure. As a general rule the Cyrix processors are the cheapest to buy and tend to be used on the cheapest motherboards in budget systems and this may well account for this difference.

The Cyrix MII 300 came with 3 settings 3.5x66 (233MHz) 3x75 (225MHz) 2.5x83 (207.5MHz) These were always wriiten on the Processor and it should run satifactorily at the stated setting. However in addition it is important to note that some other parts of the system that the processor is in may find settings other than 66MHz to be unreliable (for example PC66 ram may give rise to fatal exception 0E errors or invalid page fault illegal operations) and so running at 66MHz may prove more stable. Some people find the 66 bus setting to be the most stable and use it to stabilise problem systems that were apparent when set for the 83 bus setting (even though 83 was quoted on the processor).