PentiumPro and Pentium II/III
The Pentium II/III processors use the same dynamic execution microarchitecture as the other members of P6 family.
This three-way superscalar, pipelined micro-architecture features a decoupled, multi-stage superpipeline, which trades less work per pipestage for more stages.
The Pentium II/III processor has twelve stages with a pipestage time 33 percent less than the Pentium processor, which helps achieve a higher clock rate on any given manufacturing process.
A wide instruction window using an instruction pool.
Optimized scheduling requires the fundamental “execute” phase to be replaced by decoupled “issue/execute” and “retire” phases. This allows instructions to be started in any order but always be retired in the original program order.
Processors in the P6 family may be thought of as three independent engines coupled with an instruction pool.