Intel Atom review

With so many processors already on the market, you'd be forgiven for wondering why there's such a fuss about this one.

The answer is that the Intel Atom (formerly known by the codename "Silverthorne") is a whole new type of processor - a tiny, ultra-low-power embedded package that delivers the full capabilities of an x86 desktop CPU.

Read the full review of the first Atom-based PC here

Click here for a first look at Acer's Atom-based Aspire One

That means it can run Windows, multi-task with HyperThreading and even make a decent fist of multimedia applications with SSE3 support. It'll work with a 945G chipset, DDR2 RAM and all the components we take for granted.

Yet it does all this with a thermal design power of around 2W - incredibly, less than three per cent that of an everyday Core 2 Duo. Average power consumption is promised to be in the milliwatt range, with idle draw as low as 30mW.

This groundbreaking marriage of performance and efficiency means that Atom-powered phones and PDAs could run the same applications as desktop machines, while maintaining the battery life consumers demand. And Atom-powered PCs can take on less demanding desktop and server roles and slash power requirements.

Atomised
As you'd expect, the Atom is a more basic chip than a Core 2. It's only a single-core processor - though the forthcoming "Diamondville" Atoms will effectively combine two chips into a dual-core package. L2 cache is modest too, though not overly mean, at 512KB.

But this simplicity, combined with Intel's small-scale 45nm manufacturing process, means the chips are physically very small. Indeed, Intel boasts that, at 25mm, the Atom is the world's smallest processor. That in turn brings down the cost of silicon, so Atoms are affordable too.

It comes in two families. For mobile internet devices, the low-end Z500 and Z510 models run at 800MHz and 1.1GHz respectively, on a 400MHz front side bus, and sell for just $45. The 1.33GHz Z520 pushes the FSB up to 533MHz and sees the price rise to $65, while the 1.6GHz Z530 comes in at $95.

Alas, clearly anticipating that the greatest demand will be for the most powerful processor, Intel has stuck a hefty price premium on the top-end 1.86GHz Z540, launching it at $160 despite its small increase in clock speed over the Z530 and identical FSB.

But there's also a 200-series family for desktops and laptops. The N270 and 230 both run at 1.6GHz, with 512KB of L2 cache and a 533MHz front side bus in a 22mm² package.

The difference is that the N270 is intended for laptops such as the MSI Wind and the upcoming Eee PC update, and hence supports Intel's Enhanced SpeedStep Technology, with the deeper C4 sleep state. It has a 2.5W TDP, rather than the 2W of the Z5-series. The 230 is for desktops, and has a slightly higher TDP of 4W.

Explosive scores?
We ran tests in Vista on the latter, the 1.6GHz desktop Atom 230 with 2GB of RAM, and as anticipated despite the hysterical hype, performance isn't going to set the world alight.

Intel's CTO Justin Rattner is on record as saying the performance is about the same as the 'Banias' generation Pentium M that formed the heart of the first-generation Centrino platform back in 2003.