The Unabridged Pentium 4 IA32 Processor Genealogy

The Data Prefetcher

As a performance enhancement tool, IA32 processors have always implemented an instruction prefetcher that attempts to prefetch instructions from memory before they are actually needed. They did not, however, include a similar mechanism to fetch data into the processor before the processor asked for it.

With the advent of the Pentium® 4 processor, a data prefetch mechanism was implemented in hardware and attempts to fetch data into the processor's L2 Cache before it is actually requested. This mechanism was then migrated into the later versions of the Pentium® III processor. The data prefetcher has the following characteristics:

• The Data Prefetching hardware was implemented in the following .13μm models: Pentium® III, mobile ...