Price: 264.99 on Newegg as of 11/29/08
It is hard to believe that less than a year ago, ATI's offerings were considered to be second-rate, typically purchased only when a person couldn't afford Nvidia's better products. That stigma changed when ATI unleashed its new Radeon 4xxx series of cards, based off a new GPU which, while smaller than Nvidia's monstrous GT200, provides incredible performance. Suddenly, ATI has found itself the king of the hill.

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The Radeon 4870 1GB represents the fastest single-GPU offering that is available, and while it is listed as third in this guide, don't mistake this card as slow. In fact, the Radeon 4870 1GB is the fastest single-GPU card besides the Geforce GTX 280 listed above, and while its performance isn't up to the same level as that card in most situations, the Radeon 4870 1GB is much less expensive.
If you're going to buy a Radeon 4870, I suggest purchasing a version with 1GB of graphics memory. The 512MB versions are less expensive, but recent tests suggest that some games, when played at high resolutions, may require more memory to run quickly.