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The Atom 230 die (top) is tiny, even in comparison with the Northbridge (945GC) chipset

At CeBIT, Intel launched its Menlow platform for Mobile Internet Devices (MIDs) under the name of Centrino Atom. It uses the extremely power-efficient and compact x86 processors from the Atom Z500 series – Silverthorne – plus the US15W single chipset – Poulsbo. Intel has now followed up with two new versions of the Atom, both clocked at 1.6GHz. The Atom N270 is designed for use in budget laptops or netbooks and the the Atom 230 is designed for use in nettops – Intel jargon for cheap, budget specification desktop computers. As partnering chipsets, Intel is recommending the 945GSE and the 945GC, cut-down versions of the relatively old 945GM mobile and 945G desktop chipsets, linked to the appropriate ICH7-M or ICH7 Southbridge.
Somewhat confusingly the Atom N270 and Atom 230 both answer to the codename of Diamondville despite being so closely related to Silverthorne. Although there are versions of the latter with several clock frequencies supporting a variety of intelligent power saving modes, like the C6 recently introduced with Penryn, the Diamondvilles are less clever at saving the battery power that is so precious in MIDs, and for now they are only available at a 1.6GHz clock frequency. Nor can the Atom 230 nettop version alter its clock frequency – unlike many of the mobile Celerons, it doesn't support SpeedStep. Intel specifies a Thermal Design Power (TDP) of 4W – about twice that of an Atom Z530 at the same clock speed. For the 945GC desktop PC chipset, Intel specifies a TDP of 22W, plus another 3W for the ICH7. Even if the chipset only pulls this nominal power when it is stressed, that is still a lot of power – probably too much for the cheap passive heatsinks in nettops to cope with. The chipset contains the GMA 950, a fast DirectX 9 graphics core that is good enough for Windows Vista Aero Glass, which may be a signficant factor in the high power consumption.
The Atom N270 is less demanding. It also runs at 1.6 GHz, but it has a rated TDP of just 2.5W. It is partnered by the 945GSE chipset, a version of the 945GMS without the Macrovision copy protection license. Intel claims 4W TDP for the 945GSE. The ICH7-M is said to consume no more than 1.5W. According to Intel, Atom N270 netbooks can use passive cooling.

An Atom 230 on the cheap Intel D945GCLF motherboard has already found its way into the c't lab, where it was subjected to a range of benchmark tests. Like the VIA C3 and C7, the Silverthorne and Diamondville processors use an in-order architecture, which is more energy efficient than the out-of-order technology that has been standard in AMD and other Intel x86 processors for some years. To help compensate for the drawbacks of the in-order pipeline, at least in some applications, the Intel Atoms use hyperthreading, the Intel version of Simultaneous Multi-Threading (SMT). This makes it appear that a second logical CPU is present so the operating system runs in dual core mode. In Cinebench R10, this increases the rendering speed by fifty per cent, although an Atom 230 is still only half as fast as a Celeron 430 with 1.8GHz, core micro-architecture, at this task. The same applies to the BAPCo SYSmark 2007 (Preview) in Windows Vista. These performance figures still make the Atom 230 demonstrably faster than the VIA C7 1.2GHz, the 1GHz ULV version of which is claimed to consume just 3.5W. The VIA Nano should be faster than the Atom at the same clock speed, but it also uses more power.

Around 2,500 Atom dies will fit on a 300mm wafer

Powered by a laptop power supply using an efficient DC-DC converter, we used a picoPSU-120 and fitted with 1GByte PC2-4300 memory and a 2.5-inch SATA hard disk, the D945GCLF draws 24W from a 230V wall socket. This rises to 27W at full load on the CPU, or 33W when the GMA-950 graphics core is also stretched to capacity. The D945GCLF is therefore not as power-efficient as many Mini ITX boards equipped with the VIA C7, but it is much less power-hungry than its predecessor, the D201GLY2 with the Celeron 220. Incidentally, an Apple Mac mini is more power efficient at idle: it uses approximately 20W. At full load, however, the Mac consumes 54W, albeit for nearly four times the computing performance from its 2GHz Core 2 Duo.
There is speculation that Intel could release a dual-core version under the name Atom 330 later this year. This is likely to take the form of two Diamondville-dies in a single case.
Intel sells the Atom 230 for $29, which is a hefty price for the performance on offer compared with something like a Celeron 430, which contains a lot more silicon and costs just $34. The mobile Celeron M 320 at 1.3GHz costs $45 and the Celeron M ULV 353 – 900MHz, 5W TPD – up to $140. Intel sells the 945GC chipset for $20. The most power-efficient combination of the Atom N270 and 945GSE should sell at $44 plus $36.
We expect to see all manner of cheap notebooks or netbooks at Computex, such as the Asus Eee PC and nettops. These should include desktop versions of the MSI Wind PC or the Asus Eee Box PC.
There are a number of other differences between the Atom 230, Atom N270 and Atom Z500, such as their case designs, for example. The full report is will be published c't 13/08 (German language), available 4 June.