CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [330]
PCIe
AGP is a great way to get video information to and from video cards very quickly, but it has the downside of being a unique connector in a world where saving money is important. AGP, being based on PCI, also uses a parallel interface. When the PCI Express (PCIe) interface was developed to replace PCI, the PCIe designers worked hard to make sure it would also replace AGP. PCIe is a natural evolution for video because it is incredibly fast, using a serial communication method. Also, because PCIe is a true expansion bus designed to talk to the CPU and RAM, it also supports all of the little extras found in AGP, such as sidebanding and system memory access. All PCIe video cards use the PCIe ×16 connector (Figure 19-41). PCIe replaced AGP as the primary video interface almost overnight.
Figure 19-41 PCIe video card connected in PCIe slot
Graphics Processor
The graphics processor handles the heavy lifting of taking commands from the CPU and translating them into coordinates and color information that the monitor understands and displays.
Video card discussion, at least among techs, almost always revolves around the graphics processor they use and the amount of RAM onboard. A typical video card might be called an ATI Radeon X1950 XTX 512 MB, so let’s break that down. ATI is the manufacturer, Radeon X1950 XTX is the model of the card as well as the graphics processor, and 512 MB is the amount of video RAM.
Many companies make the hundreds of different video cards on the market, but only two companies produce the vast majority of graphics processors found on video cards: NVIDIA and ATI. NVIDIA and ATI make and sell graphics processors to third-party manufacturers who then design, build, and sell video cards under their own branding. ATI also makes and sells its own line of cards. Figure 19-42 shows an NVIDIA GeForce GTX 260 on a board made by EVGA.
Figure 19-42 NVIDIA GeForce GTX 260
Your choice of graphics processor is your single most important decision in buying a video card. Low-end graphics processors usually work fine for the run-of-the-mill user who wants to write letters or run a Web browser. High-end graphics processors are designed to support the beautiful 3-D games that are so popular today.
NVIDIA and ATI are extremely competitive, and both companies introduce multiple models of graphics processors (and therefore new models of cards) every year. However, unless you’re using the Vista Aero glass desktop, all of these extra features you see in video cards are really only for the true driving force in video cards: 3-D gaming. Your PC is capable of providing you with hours of incredible entertainment via a huge number of popular games that immerse you in 3-D environments full of light, shadows, explosions, and other amazing effects that create a fun and beautiful gaming experience.
These 3-D games have special needs to do all this amazing stuff. One need is textures. A texture is a small picture that is tiled over and over again on walls, floors, and other surfaces to create the 3-D world. Take a look at the wall in Figure 19-43. It’s made up of only three textures that are repeated over and over on the surface.
Figure 19-43 Wall of textures
Games also use hundreds of lighting effects such as transparency (water), shadows, reflection, and bump mapping—the process of laying multiple textures on the same spot to give a more textured (bumpy) look to the surface. These games are where the higher-quality graphics processors really shine. Learn more about 3-D issues in more depth in the “3-D Graphics” section later in the chapter.
Choosing a graphics processor is a challenge because the video industry is constantly coming out with new models. One of the best guides is price. The best (and newest) graphics cards usually cost around (US)$400–500. The cheapest cards cost around $50. I usually split the difference and