SINCE THEIR INCEPTION, dual-core processors have been something of an exclusive club. If you wanted to join, you had to fork over more than 300 bucks for the privilege of owning one—and getting a cheap dual-core CPU that wouldn't do a pretty accurate imitation of an acetylene torch was practically impossible. The Pentium D 805 was an affordable dual-core CPU, but because it was based on the lackluster Netburst microarchitecture—complete with Intel Hot'n'Loud technology—it wasn't the most attractive of choices.

The game is changing dramatically, however, with Intel's introduction of its new Core 2 Duo processors and AMD's retaliatory moves. Now, we have some excellent dual-core CPU options that combine solid performance with very low power use at prices around the $200 mark. What's more, because they have relatively modest clock speeds, they may have the potential to overclock like Floyd Landis in Stage 17. From Intel, there's the Core 2 Duo E6300, with 2MB of cache and microarchitectural roots in Intel's mobile products group. From AMD, there's the CPU with the longest name ever, the Athlon 64 X2 3800+ Energy Efficient Small Form Factor. You may use extra energy spitting out that massive moniker, but the chip promises to conserve thanks to its astounding 35W power rating.

We've tested these cool, cheap screamers against a range of today's best processors to see whether one of them might be the right choice for your next PC build. Also, we've taken a little extra time to explore power use, overclocking, and the impact on the Core 2 processors of dropping from 4MB to 2MB of L2 cache. Keep reading to see what we found.