Dell XPS 420 Desktop

This system is built around one of Intel's latest, greatest processors. The Core 2 Duo consists of two separate CPUs on a single die, sharing the same second-level cache. If this machine has a Core 2 Quad, that's two Duos married on the same die for a total of four cores. Meanwhile, Extreme Edition Core 2 processors, aimed at enthusiasts and gamers, are unlocked for overclocking, a process in which you increase the clock multiplier (9X, 10X, and so on) without increasing the computer's frontside bus speed (1066 MHz, 1333 MHz, or the like).

Most consumer applications can't take advantage of more than two cores, so spend the extra money on four cores only if you'll be using an application that you're certain can utilize them. Intel has strayed from the Celeron designation for its budget CPUs, so be sure to check a given processor's cache size and price (more of each roughly indicates faster performance) before buying.