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Quad-core popular, but not yet vital

Of the systems on the chart, only the Xi MTower IGE-SLI lacked a quad-core CPU (four processor cores on a single chip), the design that currently provides the most gains in complex video editing and 3D rendering. Dell's stylish XPS 720 has Intel's newer QX6800 quad-core CPU overclocked to a relatively conservative 3.2 GHz, coupled with 1066-MHz memory. If price isn't an issue, you may find more appeal in Dell's XPS 720 H2C (for which liquid cooling and a QX6800 processor overclocked to 3.46 GHz are standard specifications). However, a quad-core processor won't be of true benefit for gamers until game developers can fully harness the multicore capabilities of such CPUs.

Though a system's configuration accounts for 20 percent of its overall PC World Rating, pixel-pushing power is the essence of a gaming PC. As such, 50 percent of our rating considers the system's performance--namely, a combination of its WorldBench 6 Beta 2 score and its results in our Doom 3 and Far Cry gaming tests. (In our regular power-PC evaluations, performance is just 30 percent of the rating.)

Gaming Under Vista

These high-performance systems each shipped with, and were tested under, Windows Vista (mostly Premium or Ultimate). If you want to squeeze every last drop of performance from your games, however, you can opt to have your new gaming machine configured with Windows XP. With some vendors, you can also request that your PC be able to dual-boot between both operating systems. But DirectX 10--the Windows technology that's set to allow games to appear visually richer--is exclusive to Vista. All of the nVidia GeForce 8800-series graphics boards that the PCs on our chart use are DX10-capable, and the SLI (dual-card) technology that our top two systems employ now has vastly improved support under Vista. You can expect both nVidia and its rival, ATI, to ensure that their respective dual-card technologies support hot upcoming DX10 titles like BioShock, Crysis, and Hellgate: London. The bottom line is, it could almost be time to leave Windows XP behind for good.

The best performer in our Doom 3 test run at 1280 by 1024 resolution (with antialiasing turned on) was the Alienware Area-51 7500. Equipped with dual 768MB EVGA GeForce 8800 GTX graphics boards (which together cost at least $1200 on their own), the Alienware PC achieved an average frame rate of 165 frames per second, versus the rest of the gaming-desktop field's average of 143 fps. The Xi MTower IGE-SLI (which uses a single, roughly $280, 320MB EVGA GeForce 8800 GTS graphics board on an SLI-capable motherboard), lagged behind at 133 fps.

Though it too had just a single graphics board, a 768MB nVidia GeForce 8800 GTX, the Dell XPS 720 led the way in our GPU- and CPU-intensive Far Cry game script, which we run at 1280 by 1024 with antialiasing turned on. It averaged 202 fps, easily besting the Alienware and Gateway PCs, which achieved 187 fps and 181 fps, respectively.