Intel Atom
Intel Atom is the brand name for a line of x86 and x86-64 CPUs (or microprocessors) from Intel, previously code-named Silverthorne and Diamondville processors, designed for a 45 nm CMOS process and intended for use in ultra-mobile PCs, smart phone and other portable and low-power applications.
Background
Prior to the announcement, outside sources had speculated that Silverthorne would have competed with AMD's Geode system-on-a-chip processors, currently used by the One Laptop per Child project, and other cost- and power-sensitive applications for x86 architecture processors. However, Intel revealed on October 15, 2007[1] that it is developing another new mobile processor, codenamed Diamondville, for OLPC-type devices.
Silverthorne will be sold under the brand name "Atom", while the formerly code-named Menlow platform it sits on will be sold under the brand name Centrino Atom.[2] Intel's Atom press release only mentions "Diamondville" once and seems to imply that it too will be named "Atom".[3] This seems to strengthen speculation that Diamondville is simply a lower-cost, higher-yielding version of Silverthorne with slightly higher TDPs at slightly lower clock speeds.[4]
At Spring Intel Developer Forum (IDF) 2008 in Shanghai, Intel officially announced that Silverthorne and Diamondville are based on the same microarchitecture. Silverthorne will be called the Atom Z series and Diamondville will be called the Atom N series. The more expensive lower-power Silverthorne parts will be used in MID devices whereas Diamondville will be used in low-cost desktop and notebooks. Several Mini-ITX motherboard samples have also been revealed.[5] Intel and Lenovo also jointly announced an Atom powered MID called the IdeaPad U8.[6] The IdeaPad U8 weighs a mere 280g and has a 4.8" touchscreen providing better portability than a netbook PC and easier Internet viewing than a mobile phone or PDA.
In April 2008, an MID development kit was announced by Sophia Systems[7] and the first board called CoreExpress was revealed by a German company Lippert.[8][9] Intel offers Atom based motherboards.[10][11]
Architecture
Intel Atom retires only two instructions per cycle (similar to the 1993 Pentium). Atom implements the x86 (IA-32) instruction set; x86-64 is so far only activated for the desktop model Atom 230. N and Z series Atom models cannot run x86-64 code. [1]. Like many other designs it divides certain x86-instructions into simpler internal operations prior to execution , but to a significantly lesser extent (only ~4%) than in the Intel P6 and Intel P68 families[citation needed]. In the Atom, internal μ-ops can contain both a memory load and a memory store in connection with an ALU operation, thus being more similar to the x86 level and more powerful than the μ-ops used in previous designs[citation needed]. This enables relatively good performance with only two integer ALUs, and without any instruction reordering, speculative execution, or register renaming. Atom therefore represents a partial revival of the principles used in earlier Intel designs such as Intel P5 and the i486, with the sole purpose of enhancing the performance per watt ratio.
It has been speculated that the die space used to perform x86-decoding will put the Atom design at a disadvantage compared to other mobile architectures, such as the ARM architecture.[12] The Moorestown platform which is the successor of the Menlow Platform will be a system-on-a-chip design that uses half the power of a Silverthorne processor. The reduced power consumption will make the platform more desirable for use in smartphones and other mobile internet devices.
Silverthorne
On March 2, 2008, Intel announced the new processor (code-named Silverthorne) to be used in ultra-mobile PCs/Mobile Internet Devices (MIDs) which will supersede Intel A100. The processor is a 47 million transistor, 25 mm2, sub-3W IA processor which allows ~2500 chips to fit on a single 300 mm diameter wafer, allowing for extremely economical production.
A 1.8 GHz Atom processor's single thread performance is equivalent to its predecessor Intel A100 but should outperform it on applications that can leverage simultaneous multithreading, SSE3, and EM64T x64 extensions.[13] It has a 0.6W to 2.5 TDP rating that can dip down to .01W[14] when idle but that does not include the power consumption of the chipset. It features a 2-issue simultaneous multithreading, 16 stage in-order pipeline with 32KB iL1 and 24KB dL1 caches, integer and floating point execution units, x86 front end, a 512KB L2 cache and a 533MT/s front-side bus. The design is manufactured in 9M 45nm High-k metal-gate CMOS and housed in a 441-ball µFCBGA package."[15][16]
Diamondville
On March 2, 2008, Intel announced the new processor (code-named Diamondville) to be used in the Classmate PC Netbook. It is used in Intel's low-cost Mini-ITX motherboards (code-named "Little Falls").[17][18][19][20] It will supersede Conroe L by using Diamondville as single-core (2.5W TDP) for laptop or (4W TDP) for desktop running at 1.6-2.2 GHz each. The Diamondville Atom processor will be available in single and dual-core versions.
Power requirements
While the Atom processor itself is relatively power efficient for an X86 instruction set chip, the chipsets used with it are currently not as power efficient. For example while the N270 chip itself has a maximum TDP of 2.5W, the Intel Atom platform with the 945GSE Express chipset has a specified maximum TDP of 11.8W, with the processor only making up a relatively small portion of the total power. Individual figures are 2.5W for the N270 processor, 6W for the 945GSE chipset and 3.3W for the 82801GBM I/O controller.[21][22][23][24] Intel currently has no more power efficient chipsets ready for production.
Future
The next generation of the Atom, "Lincroft," architecture will be launched in 2H 2009 and is code-named Pineview. It will be used in Netbook/Nettop systems, and feature a system-on-chip (SOC) with an integrated single-channel DDR2 memory controller and an integrated graphics core. Pineview, like Diamondville, will be available in single and dual-core versions. It will feature HyperThreading, and is to be manufactured on a 45nm[25] or 32 nm [2] process.
Intel CEO Paul Otellini has stated that, along with other improvements, Atom (specifically Silverthorne) will shrink to the 32 nm process in 2009.[26] It has been suggested that the Atom will be the first Intel chip to transition to 32 nm due to its small size and low complexity. [3] A 32 nm Atom is expected to be demoed at the upcoming San Francisco IDF.
