The Unabridged Pentium 4 IA32 Processor Genealogy

Increased Pipeline Depth

In order to support higher clock rates, the 20 pipeline stages found in the earlier Pentium® 4 processors have been further divided into 31 stages. Intel® has not provided any information in the public domain regarding the stage names or functions, but it is widely believed that the processor stages remain unchanged (other than being subdivided into sub-stages that each contain less logic and which can therefore be clocked at a faster rate).