Photograph: Chris Manners

The ABS Ultimate X9 will appeal to adventurous buyers who are looking for maximum performance at all costs. It screamed to an incredible score of 181 in our WorldBench 5 tests, shattering our previous record score of 142 posted by the Xi MTower 64 AGL-SLI, which uses a 2.6-GHz Athlon 64 FX-60. The Ultimate X9's smashing speed is the result of pushing Intel's latest processor to the max: ABS took an Intel Core 2 Extreme X6800 processor, gave it a high-tech cooling system, and overclocked it from the stock speed of 2.93 GHz to 3.55 GHz.

The system's graphics might comes from a dual-card CrossFire configuration that employs two ATI Radeon X1900 graphics cards, each with 512MB of graphics memory. Some of our test games didn't run with CrossFire enabled, but that limitation didn't seem to hinder the system's performance. Using a single graphics card with CrossFire disabled, the system notched an average frame rate of 298 frames per second in Return to Castle Wolfenstein at 1280-by-1024-pixel resolution--the highest frame rate we've seen, and an improvement of 141 percent over our previous top scorers on that test.

Images looked great, too: The bundled 19-inch NEC 90GX2 LCD monitor produced good color and smooth motion on our test games and DVD movies. In addition, it accurately reproduced the dark, gloomy look of games like Doom 3.

To keep its overclocked processor cool, ABS introduced a large water-cooling system that dominates the interior of the Ultimate X9's case. While the cables inside the case are tidily tucked away, the water pipes running through the case interior take up a lot of space and make the system's innards look messy. The water-cooling system limits expansion options, too, since the pump, reservoir (which holds the water that carries the heat away from the processor), and associated pipes block all of the vacant externally accessible drive bays (making it a moot point that the system's big chassis is designed to house up to seven externally accessible drives). Two large, noisy fans on the case vent hot air from the other components, so the quiet advantages of water cooling are lost.

The water-cooling system isn't the only impediment to future expansion. The X9's two large graphics cards block the open PCI Express slots, leaving only one vacant PCI slot accessible. The water pipes run through two holes in the case to the radiator on the back, which makes reaching the USB 2.0 and other ports on the back rather awkward.

The system sets aside four internal bays for hard drives. Two of those drive bays were occupied in our test system by twin 150GB Western Digital Raptor drives in a 300GB striped RAID array. A dual-layer DVD burner and a DVD-ROM drive occupied two of the externally accessible drive bays.

The bundled Logitech wireless keyboard and mouse were comfortable to use. The keyboard has a number of programmable and media control keys, as well as a convenient dial for controlling the sound volume.

The overclocking that makes this system so fast falls outside Intel's specification for the processor; but ABS told us that, since it did the overclocking, it will replace the processor if it fails within the standard one-year warranty period (this guarantee isn't applicable to customers who do their own overclocking).

At $4199 (as of July 13, 2006), this is one of the most expensive systems we've seen. That's a considerable investment, but it fetches the fastest system we've seen yet.

Richard Baguley