A faster GPU allows more information to be processed in a given time, while more memory allows it to store more resulting information ready for the monitor to display. The more it can store in the VRAM, the less chance there is of the monitor having to wait for information while the GPU is processing it. This storing of information is called 'buffering'.

An important decision to make when choosing a graphics card is whether you will need high performance 3D graphics. If you want to play the latest games or run professional 3D design programs then the answer will be yes. But if you intend to use your computer for desktop and media tasks and to play some older games, the answer will be no. In fact if you do not intend to play any 3D games, graphics 'integrated' into a motherboard will do just fine.

The price of a graphics card will usually give you a reasonable idea of its performance and the sector of the market that it's aimed at. The GPU is also a very important indicator as the a cards potential performance. As with the processor, the best way to compare graphics cards is by looking at the results of benchmark tests. Tom's hardware has a comprehensive set of benchmarks for most of the currently available cards, as well as charts for multiple graphics cards.