How Laptops Work

Laptop Screen, Graphics and Sound
A laptop GPU
A laptop GPU

A graphics processing unit (GPU) is a microprocessor that handles the calculations necessary for 3-D graphics rendering. Like a CPU, a GPU produces a lot of heat. Most laptops have graphics capability built into the motherboard or have smaller graphics cards with a GPU designed specifically for laptop use. GPU manufacturers ATI and nVidia both make GPUs specifically for laptops. Laptops frequently share memory between the CPU and the GPU, saving space and reducing power consumption.

Many people don't notice a laptop's reduced graphics performance. Laptops have plenty of processing power for Web surfing and productivity applications. However, they may struggle with the latest 3-D games. A few specialty laptops, designed for gaming enthusiasts, include more powerful GPUs and additional video memory.

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A laptop displays its graphics on a liquid crystal display (LCD) screen. Most screens measure between 12 and 17 inches, and the size of the screen affects the overall size of the laptop. In addition, laptop screens can be:

  • Black-and-white (16 grayscale) or color (65,536 colors)
  • Active or passive matrix
  • Reflective or backlit

­ Active matrix displays have sharper images and are easier to read, and backlit screens are better for low-level lighting conditions.

This back view of the Toshiba's LCD panel is showing the fluorescent tube that provides the light and the screen that diffuses the light evenly over the surface.

Most laptops also have sound cards or integrated sound processing on the motherboard as well as small, built-in speakers. However, there is generally not enough space inside a laptop for a top-of-the-line sound card or a high-quality speaker. Gaming enthusiasts and audiophiles can supplement their laptops' sound capabilities with external sound controllers, which use USB or FireWire ports to connect to the laptop.