Graphics card models
Although there are a large number of graphics card vendors, there are actually only two major manufacturers of chips for graphics cards. ATI and Nvidia dominate the business, and nearly every graphics card you buy will use chips from one of these companies.
Usually, the chip in use is detailed in the product name or specifications. Cards using the same graphics chip are fairly homogenous: one graphics card using the Nvidia GeForce 6600 chip will perform roughly the same as another card using the same chip; that is not to say however, that you should not shop around. Some brands are known for offering more reliable cards that often come with slightly higher clock speeds out of the box, as well as increased, manufacturer guaranteed overclocking (see our overclocking section later) for a slightly higher price. Other factors that should come into your decision include the amount of memory a card has (128MB, 256MB etc) and its features, such as TV-Out and dual-screen support.
Unfortunately, figuring out which is the best chip for you can be challenging. The graphics chip business has become a nightmarish monstrosity involving a seeming infinite number of chip models and variations. For instance, in the Nvidia "5000 series" alone there are more than 14 discreet chips, each with different clock speeds, memory support and multitudinous other specifications. Factor in variations in memory size, interface, output support and other features and the task of choosing a graphics card becomes almost overwhelming for a casual buyer.
Nvidia are rectifying this with their next series of cards. The 7800 GTX comes in a single model. No complex variations in numbers or builds. There will be differences based on a number of the factors mentioned above, but the process of graphics card selection will grow much simpler over the next six months.
If you're not much interested in the Herculean task of unravelling the performance specifications of the various chips, we suggest the best strategy is to choose your graphics cards based on price.