From WikiChip
Transistor Density

Transistor density (xTor Density) refers to the number of transistors that are fabricated per unit area.

Overview

The transistor density of a monolithic integrated circuit refers to the number of individual transistors that can be packed into a set amount of area.

The real or effective transistor density of a die can be calculated through:

Equation effective transistor density equals StartFraction transistor count Over die area EndFraction

Variability

Although the effective transistor density provides the average density of the transistor for a particular real-world product, it is not possible to compare different product families in such a way due to numerous reasons, including:

  • Interconnect consideration
  • Performance consideration
  • Std. cell vs Full custom
  • Ratio of components on-die