Technical guide to the Intel Penryn Core 2 Processor

The Penryn CPU is another in Intel’s line of Core 2 processors and the first fabricated using its 45nm die technology. The processors replace the ‘Merom’ range of processors, the and dual- and quad-core versions catering for the differing requirements of consumer machines. The Penryn is based on the same core architecture as the current Core 2 implementations but fabricated on a smaller 45nm die using Intel’s innovative ‘high-k’ gate dielectrics and metal gate electrodes, meaning increased transistor density, increased transistor switching speed, and reduced power. Smaller transistor sizes have many benefits, not least of which is they can squeeze more chips out of a single silicon wafer (and more chips = more profit). The main technological benefit here is that more transistors can be squeezed onto the same size chip with the corollary of this being that more processor work can be done in one unit time. This technology advanced Intel’s manufacturing processes significantly ahead of those used in fabrication of the original Core 2 processors. It provided potential to once again start scaling manufacturing sizes down and, most importantly, it represented a massive leap ahead of Intel’s competitors. As an indication of the increased density available to designers, consider this: the Intel Core Quad processors harboured 582 million transistors while Penryn quad-core implementations have 820 million on smaller die. This (massively) increased transistor count is partially explained by the 6MB of level 2 cache per core, 150% of that offered by the original Core 2. Other advances The Penryn utilizes a new, faster divider which processes four bits per clock cycle rather than the two processed by...

Guide to the Intel Core 2 Quad and Extreme processors

In November 2006 Intel released the first in their range of Intel Core 2 Quad processors. Codenamed the ‘Kentsfield’, the newly released processors were two Core 2 Duo chips connected by a 1066 MHz FSB all continued on one multi-chip module. The series number for the more powerful Core 2 Extreme (‘Kentsfield XE’) was Qx6xx0, while the Core 2 Quad (‘Kentsfield’) was given the Q6xx0 code. There have been five releases of differing versions of the processor, all designed for use on desktop systems. First released was the Core 2 Extreme Qx6700 – two E6700 chips packaged on one socket. Like its Core 2 Duo predecessors, the Core 2 Extreme Quad was presented on the LGA775 platform and used Intel’s 65nm fabrication (meaning it was backwards compatible and would easily integrate with existing systems). The E6700 utilized 143mm2 dice each with 291 million transistors and each carrying 4mb DDR2-800 L2 cache. This cache memory is shared between the two dual core components meaning a total of up to 8mb shared cache. The clock speed of the combined chips matched the 2.67 GHz clock frequency of its parent. Intel had developed the preceding Core 2 Duo chips with power consumption and heat output in mind (undoubtedly mindful of the problems that beset the later Pentium models). The Core 2 Quad range was able to utilize all the advantages and manufacturing improvements introduced in these earlier models. Requiring only 1.34 volts to power the pair of processors results in much lower heat output than would perhaps traditionally have been the case: their TDP of 130 watts matched that of the later...

Illustrated guide to high-k dielectrics and metal gate electrodes

The Penryn processor debuted Intel’s 45nm fabrication, and was the first to utilize high-k gate dielectrics and metal gate electrodes. This change in technology was significant for a number of reasons: the processes used were far in advance of Intel’s competition it provided a basis on which Intel could build and scale down still further high-k dielectrics and metal gates allow decreases in transistor size and power consumption, and increases in speed and efficiency As transistors get smaller the thickness of the silicon dioxide (Gate Oxide on the diagram below) needs to reduce in order to increase capacitance. Increased capacitance means increased current and improved performance, while reduced transistor size means more transistors on a die. More transistors on a die means more computing power. Processor technology means that getting smaller and working faster and more efficiently complement perfectly. The problem arises when the thickness of silicon decreases past a certain level and it gets so small that current begins to leak out. The electrons undergo a process known as tunnelling: they escape the transistor and dissipate which means the gate is less efficient, resulting in increased power consumption and reduced reliability. This loss in efficiency is one of the reasons chips (think later Pentiums) that had many transistors crammed onto them would produce such high TDP. After a certain point further reduction in size becomes impractical, the physical limit of Moore’s law is reached, and a new approach is needed. Enter high-k dielectrics. A high-k dielectric is a material with a high dielectric constant (k) which, in this case, replaces the silicon dioxide layer of the transistor. A...

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