Process-Architecture-Optimization was a temporary development model introduced by Intel for their mainstream microprocessors in 2016 following the phase-out of their Tick-Tock model as a result of major delays and challenges involving their 10 nm process.

Under the Process-Architecture-Optimization Model:

• Process - With each process, Intel advances their manufacturing process technology in line with Moore's Law. Each new process introduces higher transistor density and generally a plethora of other advantages such as higher performance and lower power consumption. During a "process", Intel retrofits their previous microarchitecture to the new process which inherently yields better performance and energy saving. During a "process", usually, just a few features and improvements are introduced.

• Architecture - With each architecture, Intel uses the their latest manufacturing process technology from their "process" to manufacture a newly designed microarchitecture. The new microarchitecture is designed with the new process in mind and typically introduces Intel's newest big features and functionalities. New instructions are often added during this cycle stage.

• Optimization - With each optimization, Intel improves upon their previous microarchitecture by introducing incremental improvements and enhancements without introducing any large charges. Additionally, the process itself enjoys various refinements as it matures. (For example with Kaby Lake, an optimized process called "14 nm+" is used. The enhanced process had a number of transistor-level modifications done to it (e.g. taller fins) allowing for higher frequency at identical voltage levels.)

Roadmap

Intel PAO Roadmap
Cycle	Process	Introduction	Micro­archi­tecture
Process	14 nm	2014	Broadwell
Architecture	14 nm	2015	Skylake (Client)
Optimization	14 nm+	2016	Kaby Lake
Optimization	14 nm++	2017	Coffee Lake, Skylake (Server)
Optimization	14 nm++	2018	Whiskey Lake
Optimization	14 nm++	2019	Cascade Lake, Cooper Lake