Have you noticed Atom-based laptops seem to be getting nicer? The latest models sport bigger screens, more RAM, and slimmer and lighter designs than anything that's come before. They are also using versions of the Atom processor that weren't originally intended to be used in laptops.

The Atom processor family tree is split into two main branches. The side of the family that's gotten the most attention so far is the 1.6GHz Atom N270, formerly called Diamondville. This chip is the heart of Intel's netbook platform, an Atom processor paired with Intel's 945GSE Express chipset and intended for use in small, portable laptops, like Asustek Computer's Eee PC and Acer's Aspire One.

The N270 is closely related to two other chips, the 1.6GHz Atom 230 and 1.6GHz Atom 330. Both chips are designed for use in low-end desktops, a product segment that Intel calls nettops.

The other side of the Atom processor family is the Z-series, formerly called Silverthorne, a range of chips released before the N270 that run at clock speeds from 800MHz to 1.86Ghz.

"Certainly, the bulk of the volume and majority of netbook designs are and probably will remain on the N270. That said, if customers want to use a Z-series for these laptop designs, that is their choice," said Bill Calder, a spokesman for the chip maker.

Both the Z-series and the Atom chips found in netbooks and nettops have the same basic processor core. The only difference, apart from clock speeds, is that the Z-series processors support Intel's VT virtualization technology and Demand-Based Switching, a technology that reduces power consumption by adjusting the chip's voltage and frequency depending on how heavy the processing load is at a given moment.

Another feature of the Z-series is its chipset. Unlike the two-chip 945GSE Express used with the N270, the Z-series processors are paired with Intel's single-chip System Controller Hub US15W chipset, formerly called Poulsbo. The single-chip chipset helps cut power consumption and allows hardware makers to put Atom processors inside smaller computers.

The Z-series chips were originally designed for small, handheld computers that Intel calls mobile Internet devices, but they're now making their way into a new crop of Atom-based laptops, such as Sony's P Series.

The P Series mini-laptop, unveiled at the Consumer Electronics Show in Las Vegas this week, is arguably the nicest of the new machines. Priced at US$900, the P Series has a 1.33GHz Atom Z520 processor, 8-inch widescreen display, 2GB of RAM, a 60GB hard drive, a built-in GPS and 3G modem, as well as Wi-Fi and other features packed inside a sleek 680-gram package that's just 2 centimeters thick.