Overclocking Pentium III's using by breaking the fixed multiplier.

[scsiraider]

Every one here must know how to use the tape method on the VID pins of a PIII. Well if the multiplier is fixed on the cpu board then it has to send a signal out of one of the pins to tell the bios and mobo what multiplier it is using. Has anyone tried this or know what pin(s) that signal transmits on.

Question two does anyone know if it is necessary to increase the voltage to a PIII when oc'ing it using the FSB to help with stability?

[Tim-]

The bios queries the CPUID instruction imbedded in the cpu microcode and knows the particulars of the chip from the response. It determines the Xeon and Celeron familes by the L2 cache information it contains. This information can not be altered directly. The multiplier value for the chip is embedded within the microcode and is not available to the bios for change.

[wild_andy_c]

Consider the T-Bird and the way in which it is locked, the P3 and Celeron2 are merely an under the surface idea of this that cannot be algged with remedial attention and tenure.

With regard to blocking a signal - you'd be blocking a whole lot more than just a multiplier signal if youy blocked any pin on the S370 type chip other than a Voltage switch, sense, ID or core ground.

.....You gotta imagine that this information about fixed multiplier is firing from all over the chip all the time through various legs.

Had it have been as simple as a couple of pins on the processor base - do you not think that motherboard manufacturers would have addressed it on SECC, SEPP, S370 and FCPGA processors in all to give them the same overclocking functionality as the Athlon??

With regard to voltage - yes it is necessary to up volts in order to gain stability at higher FSB's.