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Bonnell (microarchitecture)

CPU microarchitecture

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Through Microarchitecture, Arithmetic logic unit and Server (computing)

The Bonnell microarchitecture therefore represents a partial revival of the principles used in earlier Intel designs such as P5 and the i486, with the sole purpose of enhancing the performance per watt ratio. However, hyper-threading is implemented in an easy (i.e. low-power) way to employ the whole pipeline efficiently by avoiding the typical single thread dependencies.

First generation cores

Silverthorne microprocessor

On 2 March 2008, Intel announced a new single-core Atom Z5xx series processor (code-named Silverthorne), to be used in ultra-mobile PCs and mobile Internet devices (MIDs), which will supersede Stealey (A100 and A110). The processor has 47 million transistors on a 25 mm2 die, allowing for extremely economical production at that time (~2500 chips on a single 300 mm diameter wafer).

An Atom Z500 processor's dual-thread performance is equivalent to its predecessor Stealey, but should outperform it on applications that can use simultaneous multithreading and SSE3. They run from 0.8 to 2.0 GHz and have a TDP rating between 0.65 and 2.4 W that can dip down to 0.01 W when idle. They feature 32 KB instruction L1 and 24 KB data L1 caches, 512 KB L2 cache and a 533 MT/s front-side bus. The processors are manufactured in 45 nm process. Poulsbo was used as System Controller Hub and the platform was called Menlow.

Diamondville microprocessor

On 2 March 2008, Intel announced lower-power variants of the Diamondville CPU named Atom N2xx. It was intended for use in nettops and the Classmate PC. Like their predecessors, these are single-core CPUs with Hyper-Threading.

The N270 has a TDP rating of 2.5 W, runs at 1.6 GHz and has a 533 MHz FSB. The N280 has a clock speed of 1.66 GHz and a 667 MHz FSB.

On 22 September 2008, Intel announced a new 64-bit dual-core processor (unofficially code-named Dual Diamondville) branded Atom 330, to be used in desktop computers. It runs at 1.6 GHz and has an FSB speed of 533 MHz and a TDP rating of 8 W. Its dual core consists of two Diamondville dies on a single substrate.

During 2009, Nvidia used the Atom 300 and their GeForce 9400M chipset on a mini-ITX form factor motherboard for their Ion platform.

First generation power requirements

Although the Atom processor itself is relatively low-power for an x86 microprocessor, many chipsets commonly used with it dissipate significantly more power. For example, while the Atom N270 commonly used in netbooks through mid-2010 has a TDP rating of 2.5 W, an Intel Atom platform that uses the 945GSE Express chipset has a specified maximum TDP of 11.8 W, with the processor responsible for a relatively small portion of the total power dissipated. Individual figures are 2.5 W for the N270 processor, 6 W for the 945GSE chipset and 3.3 W for the 82801GBM I/O controller. Intel also provides a US15W System Controller Hub-based chipset with a combined TDP of less than 5 W together with the Atom Z5xx (Silverthorne) series processors, to be used in ultra-mobile PCs and MIDs, though some manufacturers have released ultra-thin systems running these processors (e.g. Sony VAIO X).

Initially, all Atom motherboards on the consumer market featured the Intel 945GC chipset, which uses 22 watts by itself. As of early 2009, only a few manufacturers are offering lower-power motherboards with a 945GSE or US15W chipset and an Atom N270, N280 or Z5xx series CPU.

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