Video card pipelines are part of the internal structure of a graphical processing unit (GPU). The GPU is the video card’s equivalent to a motherboard’s computer processing unit (CPU). The number of pipelines built into the GPU dictates in part how fast the video card can process data to the screen.
While the number of pipelines isn’t important for word processing, spread sheets or other text-based tasks, it does figure prominently when it comes to graphics. Watching DVDs on a computer, streaming video and gaming all require intense processing, or rapid screen-fill. In such cases, the number of video card pipelines helps to make the difference between a blazing experience and a poor one.
Pipelines allow the video card to process pixel data in tandem along parallel lines. A rough analogy might be that of a broadband connection with plenty of real-estate for more than one frequency or “lane” to carry data. The more real-estate, the more data lanes are possible. In the same way, the more pipelines on a video card, the more data can be processed in parallel, leading to a faster screen-fill.
For example, if one video card has eight pipelines, and another has 16, all else being equal, the card with 16 pipelines will be twice as fast. This makes for smoother motion in both movies and gaming, and a more realistic three-dimensional experience.
Another feature to consider in addition to pipelines is memory bus. Most cards today have either 128-bit or 256-bit buses. On-board memory can be one of several types: for example, DDR2 is slower than DDR3, while DDR4 is even faster. Finally, there is the GPU clock speed. Just like a CPU, a GPU can have a slow or fast clock speed. The most popular chipsets are manufactured by nVidia as the GeForce series and by Array Technologies Incorporated (ATI) as the Radeon series.
Taking all of these factors into consideration, a decent video card will have a combination of features that work together for good performance. The nVidia-based GeForce 6800GT series was the gaming card of choice for nearly two years after its release in the fourth quarter of 2004. A 256-bit bus with 16 pipelines, 256 megabytes (MB) of DDR3 memory and a clock speed of 350-450 megahertz (mHz) gave it a bandwidth rate of 32-35 gigabytes per second (GB/ps).
The more modestly priced and newer GeForce 7600GT series has a slower 128-bit bus and only 12 pipelines, but compensates with a faster clock speed, matching the performance of the 6800GT on many benchmarks. The 7600GT series supports newer technologies, including Microsoft’s Vista operating system, and ranks as a solid mid-level card. The ATI equivalent is the Radeon X1650XT.
As of fall 2006, cutting edge gaming cards feature not one, but two GPUs. This doubles the pipelines, the bus and memory, delivering bandwidth just over 76 gigabytes per second. The price of these cards, however, is likely to discourage anyone but the most dedicated gamers.
When shopping for a graphics card, compare specifications. The most expensive card in its class isn’t always the best choice. Number of pipelines, memory bus, type of memory and clock speed are each important; and be sure the card supports the latest graphical software engines. To save money, keep an eye out for rebates and discount coupons. Online customer reviews are also useful.
