Apologies To Asus - P5AD2 Runs Within Specs
This is how we first measured the Northbridge voltage. Unfortunately, measuring voltage at the regulator did not show the right value since Asus uses an efficient regulator scheme that supplies both Northbridge and DDR2 memory.
When we first measured Northbrige voltages for this review, we used the voltage regulator pin 2 to get the values using a voltmeter. Unfortunately, we did not take into account that the P5AD2 is based on a regulator scheme which is very efficient (~ 85%) and uses one regulator to provide basic voltage for the Northbridge and the DDR2 memory. This technology uses a silicon diode to charge a capacitor up to the exact voltage you wish to deliver. Hence, measuring the voltage at the corresponding capacitors or on the cathode side of the diode will result in the correct value.
As a result, we assumed the DDR2 output voltage was also the voltage that was delivered to the Northbridge, accusing Asus to operate the Northbridge chips at over 2 Volts - which in fact is not the case. Our apologies to Asus, since their boards run within specs. Only the P5GD2 we received first runs at a slightly higher voltage. Here is an impression on how we measured the Northbridge voltage correctly:
This is how the voltage output of Buck regulator schemes needs to be measured.
