The processor is where your computer does all its "thinking"
There are two major brands of processors on the market: Intel and AMD. The Compaq Presario desktop uses a socket AM3 motherboard, which only accepts socket AM3 processors, which are all made by AMD, which has three types of socket AM3 processors designed for different levels of performance. Which of these processor is right for you depends on what you need your computer to do.
AMD Sempron
The Sempron processor is the most affordable AM3-socket processor on the market, and it is also the most basic. If you are using a Presario laptop or Netbook, or if you are using a Presario desktop to do office tasks such as email, word processing, and accessing the Web, the little Sempron has enough power to get the job done. You get 256KB full-speed L2 cache, and some models include an integrated DDR2 memory controller. You could certainly do worse.
AMD Athlon II X2
If you're planning on using your Presario to rip and encode CDs and DVDs, or setting it up as a media center, the Athlon II X2 is a significant step up from the Sempron. This processor is optimized for the most advanced desktop effects Windows 7 is able to throw at it, and in turn, Windows 7 is able to use the AMD PowerNow! 3.0 power management feature, which is built into the processor and ready to go. This is a dual-core processor, but there are tri- and quad-core Athlon IIs available as well. While the Sempron has a sufficient 256KB L2 cache, the Athlon II has an incredible 2MB L2 cache.
AMD Phenom II X2
There's not much you can't do with the Phenom II. From movies to music to video editing to redirecting ballistic missiles, this monster does it all, except for redirecting ballistic missiles. Combine this processor with an HD video card, and you have a home entertainment powerhouse. You might want to upgrade your CPU cooling system, as this processor does a lot of work very quickly, and will cook itself without a fairly advanced cooling system in place. Like the Athlon II, the Phenom comes in dual-core, tri-core, and quad-core models. Unlike the Athlon II, 5- and 6- core models are available as well.
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