Gecko's CPU Library

Intel Core 2 (Allendale) processors

Introduction: January 2007


The Core 2 brand refered to a range of Intel's consumer 64-bit dual-core and 2x2 MCM quad-core CPUs with the x86-64 instruction set, based on the Intel Core microarchitecture, derived from the 32-bit dual-core Yonah laptop processor. Note: the Yonah's silicon chip or die comprised two interconnected cores - each similar to those branded Pentium M. The 2x2 MCM dual-die quad-core CPU had two separate dual-core dies (CPUs) - next to each other - in one quad-core MCM package. The Core 2 relegated the Pentium brand to a lower-end market, and reunified laptop and desktop CPU lines, which previously had been divided into the Pentium 4, D, and M brands.

The Core microarchitecture returned to lower clock speeds and improved processors' usage of both available clock cycles and power compared with preceding NetBurst of the Pentium 4/D-branded CPUs. Core microarchitecture provided more efficient decoding stages, execution units, caches, and buses, reducing the power consumption of Core 2-branded CPUs, while increasing their processing capacity.

The Core 2 brand was introduced on July 27, 2006 comprising the Solo (single-core), Duo (dual-core), Quad (quad-core), and Extreme (dual- or quad-core CPUs for enthusiasts) branches, during 2007.

The Core 2-branded CPUs included: "Conroe" and "Allendale" (dual-core for higher- and lower-end desktops), "Merom" (dual-core for laptops), "Kentsfield" (quad-core for desktops), and their variants named "Penryn" (dual-core for laptops), "Wolfdale" (dual-core for desktops) and "Yorkfield" (quad-core for desktops). Note: for the server and workstation "Woodcrest", "Clovertown", and "Tigerton" CPUs saw the Xeon brand.

The Core 2 branded processors featured the Virtualization Technology (except T52x0, T5300, T54x0, T55x0 with stepping "B2", E2xx0, E4x00 and E8190 models), Execute Disable Bit, and SSE3. Their Core microarchitecture introduced also SSSE3, Trusted Execution Technology, Enhanced SpeedStep, and Active Management Technology (iAMT2). With a Thermal Design Power (TDP) of up to only 65W, the Core 2 dual-core Conroe consumed only half the power of less capable, but also dual-core Pentium D-branded desktop chips with a TDP of up to 130W (a high TDP requires additional cooling that can be noisy or expensive).

The Allendale core

There was contention about the previously available low-end Core 2 Duo Conroe desktop processors (E6300, at 1.86GHz and E6400, at 2.13GHz, both with 2MB L2 cache), whether they were specimens of the Allendale core. Prior to Q1 2007, all E6300 and E6400 processors released were Conroe (4MB L2 cache) cores with half their L2 cache disabled. The Allendale core, manufactured with 2MB L2 cache in total, offered a smaller die size and therefore greater yields.

Another difference between the premium E6000 series (Conroe core) and the E4000 series (Allendale core) was the front side bus clock rating. The E4000 series were rated to run on a quad-pumped 200MHz FSB (800MT/s) while the E6000 series were rated to run on a quad-pumped 266MHz FSB (1066MT/s). The E4000 series also lacked support for Intel VT-x instructions.

The Core 2 Duo E4300 used an Allendale core, released on January 21, 2007. The Allendale processors used a smaller mask with only 2MB of cache, thereby increasing the number of chips per wafer. Allendale processors were produced in the LGA775 form factor, on the 65 nm process node. E6300 and E6400 CPUs had been made from both the 4MB Conroe die and the 2MB L2 Allendale die. The steppings of the chip differed depending on the die used: the Conroe-based E6300 and E6400 were stepping B2 and the Allendale-based E6300 and E6400 were stepping L2.

Initial list price per processor in quantities of 1000 for the E4300 was US$163. A standard OEM price was US$175, or US$189 for a retail package. Price cuts were enacted on April 22, 2007, when the E4400 was released at $133 and the E4300 dropped to $113. Allendale processors with half their L2 cache disabled were released in mid-June 2007 under the Pentium Dual-Core brand name. The working cache memory was reduced by half again when the Allendale core was released under Intel's Celeron brand; the Celeron E1200 had a 512KB L2 cache shared between its two cores.

On July 22, 2007, an E4500 Allendale was launched, phasing out the E4300 model. This was accompanied by a price cut for the E4400 model.

Source: Wikipedia, the free encyclopedia.