Sam's Computer Geek Page
If you JUST minimize the pesky ad it will quit popping up

• All the 3D enhanced processors (Intel, AMD, Cyrix, IBM) require two different voltages to be supplied to the CPU simultaneously.
• This means the motherboard must have at least two regulators on board.
• The two voltages must be correct for the chosen CPU. The required combination of voltages varies even within the offerings of a given manufacturer between CPU speeds. Some even have two CPU versions at the same speed with different voltage requirements. You will need to research both your mainboard and the specific CPU to determine compatibility. There are boards that have the correct frequency settings but not the required voltages for the CPUs that were produced to operate at those frequencies. (They guessed wrong about future CPUs).
• Most MMX capable boards are backward compatible to single voltage CPUs. This is commonly accomplished by a jumper setting. Usually the settings are identified by something similar to "P54C / P55C". P54C is the single voltage setting. P55C is the dual voltage setting. This may be identified in other ways such as: "MMX--enabled/disabled", "MMX/non-MMX".

Hot Roddin' Chips
• Overclocking
  --NOT Recommended unless you can afford to smoke your chip.--
  Going more than about 10% over the CPUs rated speed can be disastrous.
• Under-clocking is considered safer (CPU runs cooler - longer life) but should still be only a notch or two from the rated CPU speed.
  This may allow you to use a faster CPU temporarily in a slower board until you can upgrade the motherboard. But don't try a MMX CPU on a non-MMX board, that won't work.
• Faster BUS speeds increase motherboard performance - to a point.
• Faster CPU speeds increase CPU performance - to a point.
• Beyond "a point" overheating WILL shorten component life (or kill them straight-away) and may cause data or system errors. Overheated components can be unreliable without actually failing.
• In some cases underclocking the CPU and over-clocking the BUS can increase the overall system performance.
  --Example: a 150MHz CPU (3.0 X 50MHz BUS) may have better overall performance set to 133MHz (2.0 X 66MHz BUS)---The CPU would be running ~12% slower but the motherboard is running ~32% faster. Which is better can only be determined by testing and varies with different applications.
  In this case if the settings are available try 150MHz (2.0 X 75MHz BUS) Some memory or add-in cards may not run well at this frequency. Experimentation would be required.
  
  Ever notice that a P100 is very close to a P120, a P133 is faster than a P150, and a P166 is faster than a P180. It isn't your imagination. The slower P100,133,166 CPUs run at 66MHz - the others at 50 or 60MHz. The result is better overall performance with slower CPUs.

• Most (but not all) motherboards advertised to P200-MMX will actually run
  P233-MMX and K6-233(classic) CPUs
  EVEN IF THERE IS NO 3.5x MULTIPLIER ON THE BOARD.
  These CPUs were designed to be backward compatible with slightly older (at the time) motherboards. This is accomplished internally by the CPU.
• To make this work you need:
  • An MMX capable motherboard.(See above)
    
  • Set the board up for the dual voltages as required for the CPU.
  • Set the BUS and Multiplier to 1.5 x 66MHz.(Same as a P100MHz CPU)
• When these CPUs sense 1.5 x 66MHZ *AND* and the proper TWO voltages they INTERNALLY multiply the frequency to achieve the 233MHz.
• This trick works on motherboards that 100% followed Intel's MMX specs--From my experience I'd say over 95% did.
• I have only ever heard of this not working on 3 boards. Two were different models of Shuttle mainboards, I don't remember the make of the third at the moment but it wasn't Shuttle.
• I have successfully done this myself on boards by: Asus, Abit, FIC, PcChips, Hsing Tech, Micronics, TekRam, Alton, Amptron, and Eurone.
  I personally have NEVER had it not work.
• Shuttles site has a fix posted for one of the two models with the problem. It requires installing a resistor under the motherboard between two pins on the ZIFF socket. This indicates to me the problem stems from deviating from 100% compliance to the MMX spec in order to accommodate only those CPUs on the market when the boards were released.
• Some examples of the P233-MMX and K6-233(classic) situation were the information was updated on the manufacturers site:
  • Asus's 233-MMX Page (See the second note)
  • Asus's VX97 CPU Compatibility Page (Find the Blue dots - be patient, the dots load last)
  • There are other examples. I'll post more when I find them again ;-)