I needed to change Athlon's core voltage a bit to run it at all the different clock speeds. You may think that I'm talking of higher voltages, but as a matter of fact the opposite was the case. Athlon would not run at 500 or 550 MHz unless I lowered the core voltage down to 1.45 V. On the other side, I only had to raise the core voltage from the default 1.6 V to 1.65 V and Athlon worked beautifully at 700 and 750 MHz. 800 MHz were left to the super-cooled Kryotech-Athlon , since I didn't want to tamper with my Athlon at higher voltages than 1.7 V and this was obviously not enough to run it at 800 MHz without Kryotech's cooling.

Pentium III used to 2 V for 500 and 550 MHz, the default of 2.05 V for 600 MHz and for 650 MHz I raised the core-voltage to 2.1 V. Pentium III did definitely not like any higher voltage than that, it responded with definite crashes to 2.2 V.

Both processors are produced in .25µ-technology and so it's pretty impressive to see the differences. Intel's Pentium III can barely reach the 650 MHz at 2.1 V, while AMD's Athlon runs just fine at up to 750 MHz at only 1.65 V.

System Setup