The Unabridged Pentium 4 IA32 Processor Genealogy

Introduction

The initial steps in the system startup are as follows:

1.	The power is off.
2.	When the power is turned on, the power supply keeps the PowerGood signal deasserted to the chipset until the supply voltages are up and stable. During this period of time, the chipset keeps reset asserted to the processor(s) and to all other devices until the power is stable and for a period of time afterwards (to allow sufficient time for clock generators to spin up, etc.).
3.	While reset is still asserted to the processors, the chipset (specifically, the Root Complex, MCH, or North Bridge) drives the contents of its processor configuration register onto the FSB signal lines that provide startup configuration information to the processors (see “Pentium® ...