Enhanced Pentium M based

Main article: Enhanced Pentium M (microarchitecture)

The original Core brand refers to Intel's 32-bit mobile dual-core x86 CPUs, which derived from the Pentium M branded processors. The processor family used a more enhanced version of the Intel P6 microarchitecture. It emerged in parallel with the NetBurst microarchitecture (Intel P68) of the Pentium 4 brand, and was a precursor of the 64-bit Core microarchitecture of Core 2 branded CPUs. The Core brand comprised two branches: the Duo (dual-core) and Solo (Duo with one disabled core, which replaced the Pentium M brand of single-core mobile processor).

Intel launched the Core brand on January 6, 2006 with the release of the 32-bit Yonah CPU – Intel's first dual-core mobile (low-power) processor. Its dual-core layout closely resembled two interconnected Pentium M branded CPUs packaged as a single die (piece) silicon chip (IC). Hence, the 32-bit microarchitecture of Core branded CPUs – contrary to its name – had more in common with Pentium M branded CPUs than with the subsequent 64-bit Core microarchitecture of Core 2 branded CPUs. Despite a major rebranding effort by Intel starting January 2006, some companies continued to market computers with the Yonah core marked as Pentium M.

The Core series is also the first Intel processor used as the main CPU in an Apple Macintosh computer. The Core Duo was the CPU for the first generation MacBook Pro, while the Core Solo appeared in Apple's Mac mini line. Core Duo signified the beginning of Apple's shift to Intel processors across their entire line.

In 2007, Intel began branding the Yonah core CPUs intended for mainstream mobile computers as Pentium Dual-Core, not to be confused with the desktop 64-bit Core microarchitecture CPUs also branded as Pentium Dual-Core.

September 2007 and January 4, 2008 marked the discontinuation of a number of Core branded CPUs including several Core Solo, Core Duo, Celeron and one Core 2 Quad chip.

Core Duo

Intel Core Duo (product code 80539) consists of two cores on one die, a 2 MB L2 cache shared by both cores, and an arbiter bus that controls both L2 cache and FSB (front-side bus) access.

Codename (main article) Brand name (list) L2 Cache Socket TDP Yonah Core Duo T2xxx 2 MB Socket M 31 W Core Duo L2xxx 15 W Core Duo U2xxx 9 W Core Solo

Intel Core Solo (product code 80538) uses the same two-core die as the Core Duo, but features only one active core. Depending on demand, Intel may also simply disable one of the cores to sell the chip at the Core Solo price—this requires less effort than launching and maintaining a separate line of CPUs that physically only have one core. Intel used the same strategy previously with the 486 CPU in which early 486SX CPUs were in fact manufactured as 486DX CPUs but with the FPU disabled.

Codename (main article) Brand name (list) L2 Cache Socket TDP Yonah Core Solo T1xxx 2 MB Socket M 27–31 W Core Solo U1xxx 5.5–6 W