The Unabridged Pentium 4 IA32 Processor Genealogy

Determining if a New Update Supersedes a Previously-Loaded Update

Before loading a new update into a processor, follow this procedure:

1.	First, verify that the new image is appropriate for the processor (see “Processor/Image Match Determination” on page 636).
2.	Obtain the Update Revision field from the header of the new Microcode Update image.
3.	Obtain the signature of the update (if any) previously loaded into the processor (see “CPUID Enhanced to Supply Update Signature” on page 636).
4.	If the Update Revision field of the new update image is greater than the signature obtained from the processor (i.e., the signature of the update that currently resides in the processor), then load the new update image into the processor (see “The Bare Bones ...