Although it's not the first, the ASUS C90S is one of the more elegant implementations of a desktop CPU in a notebook, even if it is an over-the-top, and only marginally effective, approach to gaining performance. Built for gaming, the C90S uses an Intel Conroe processor, the E6600 2.4GHz 65nm (nanometre) desktop CPU, and employs some innovative cooling that allows this machine to maintain its slim figure without compromising the thermal dynamics.

Of course, no gaming notebook is complete without a graphics card, even if there is a desktop CPU on-board. In this case ASUS has installed an NVIDIA 8600M GT with 512MB of video RAM to play with. It's not the most powerful card on the market but it will still play the latest games, even if you're reduced to lower quality settings or lower resolutions. If you want really impressive gaming performance you'll want to look for a notebook offering NVIDIA's 8700M GT or even better, an 8800M GTX. As we'd expect for a notebook with this target market, 2GB of DDR2 667MHz RAM has been installed, a bare minimum for modern gaming.

So, why the desktop CPU? Notebook CPUs, at least from Intel, are already pushing the 2.6GHz limit, so why go to the effort of fitting a desktop CPU? Probably the biggest difference is the front side bus (FSB) speed of the desktop models. The E6600 enjoys a FSB of 1066MHz, where the fastest notebook CPU, the 2.6GHz T7800, can only offer an 800MHz FSB. For those not so familiar with the term, a FSB is essentially a highway over which the CPU and memory pass information. The bigger it is the faster the information travels back and forth.

There is a down side to this, however. The E6600 has been installed on a notebook motherboard with an Intel 945PM chipset and the 945PM chipset only supports a 667MHz FSB, creating a bottleneck. This problem will become more evident in the benchmarks below. To counter for the increased thermal footprint of the desktop CPU, ASUS has installed a large cooler on the back of the notebook, which is surprisingly discreet when the notebook rests on a desk.

On the upside of things, the ASUS C90S is overclockable. In a similar move to MSI's TurboBook GX600, it isn't manually overclockable per say, but it does have a preset 15-20 per cent overclocking feature built into the ASUS power management software, Turbo Gear. Unfortunately this launches the notebook into super cooling mode, which sounds like a Boeing 747 warming up its turbines, at least when it's under load.

Let go of the CPU issue for a moment and let's take a look at what else is interesting on this notebook. For starters it offers both HDMI and e-SATA ports, two features that are going to keep this model current for a while into the future, and it also includes a digital TV tuner. It has also been designed for easy upgrades. The bottom of the machine can be easily removed and the CPU, RAM, hard drive or even graphics board can be removed and replaced (using compatible parts only) with relative simplicity.

We ran a couple of tests to check the performance of the CPU in comparison to other notebooks. Using iTunes to convert 53 minutes worth of WAV files to 192Kbps MP3 files took 73 seconds. This beat the Zepto Znote 6625WD with a T7700 2.4GHz notebook CPU by just two seconds and wasn't as speedy as the Toshiba Satellite X200 (PSPBUA-00N007) using a T7800 2.6GHz notebook CPU, which took just 66sec to perform the same task. Overclocking the CPU using Turbo Gear improved the ASUS C90S' time to 65sec.

In 3DMark 2006 we got a score of 3365, which is just enough to play the latest games with reasonable frame rates. In 3DMark 2001 SE the score of 21,852 clearly shows older games will not challenge this notebook.