The Core microarchitecture initially did not reach the clock rates of the NetBurst microarchitecture, even after moving to 45 nm lithography. High power consumption and heat intensity, the resulting inability to effectively increase clock rate, and other shortcomings such as an inefficient pipeline were the primary reasons why Intel abandoned the NetBurst microarchitecture and switched to a different architectural design, delivering high efficiency through a small pipeline rather than high clock rates.
It is based on the Yonah processor design and can be considered an iteration of the P6 microarchitecture introduced in 1995 with Pentium Pro.
The Intel Core microarchitecture (formerly named Next-Generation Micro-Architecture) is a multi-core processor microarchitecture unveiled by Intel in Q1 2006. P6 family ( Celeron, Pentium, Pentium Dual-Core, Core 2 range, Xeon).