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A Closer Look at Graphics for Laptop Computers

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A Closer Look at Graphics for Laptop Computers

Where graphics technology on laptop PCs was once regarded as the weak link in the system, many of today's laptops have graphics chipsets that compete favorably with their desktop counterparts


Until recently, most laptop computer buyers were more concerned about issues such as battery life, hard disk size, and memory upgradeability than a laptop computers graphics. However, with the rise in popularity of laptop computers as a mainstream computing solution (in May 2003, laptop computers outsold desktop computers for the first time ever), buyers are now concerned about the details of how a particular model creates and displays graphics.

Getting the right graphics solution for your needs is far more critical for laptop computer users than for desktop computer users. Unlike desktop computers, which typically allow you to disable onboard video or replace a low-end AGP card with a faster, better AGP card, the graphics subsystems in laptop computers are not user-replaceable except in rare situations. In my book Upgrading and Repairing Laptops I discuss the methods available on a few models to upgrade onboard graphics. However, with most laptop computers, the time to consider the portable graphics solution thats right for you is when you purchase your computer. Choose an inadequate solution, and your only recourse is to replace your system.

In this article, you will learn about the different types of graphics for laptop computers and how to determine whether a particular laptop computers graphics are suitable for your needs.

Types of Laptop Computer Graphics

Laptop computers use two major methods to display graphics:

  • Video integrated with the North Bridge or Graphics Memory Hub chip on the motherboard
  • A separate (discrete) graphics chip or module on the motherboard

From a computer vendors standpoint, using a motherboard chipset which includes integrated graphics is a less-expensive solution for two reasons. One, the vendor does not need to design an interface to a discrete graphics chip or module. Two, the vendor does not need to purchase the graphics chip and memory for the graphics subsystem; instead, the graphics integrated into the motherboard chipset shares main memory. That said, whats good for the vendor isnt necessarily good for you, the user.

Comparing Chipset and Discrete Graphics Solutions

At first glance, it might not seem important where the graphics on your laptops screen come from. However, the differences between how integrated and discrete graphics solutions perform can have a profound difference on your satisfaction with a given system.

Generally speaking, integrated graphics solutions have the following characteristics:

  • Shared memory. Integrated graphics use a portion of main system memory. For example, a system with 256MB of installed RAM which has a 32MB integrated graphics solution has only 224MB usable RAM (256-32=224).
  • Relatively slow performance because of the use of shared memory thats not optimized for video display, the chipsets performance of tasks other than video display, and the slow core clock speed of the integrated solution.

Many integrated solutions also lack support for multiple displays (using the internal LCD display and a display connected to the LCD port as separate displays) or DirectX 8.x or greater.

If you use a laptop primarily for office work (data entry and web surfing), an integrated solution is probably adequate for your needs. However, if you are looking for a 3D graphics (gaming/modeling) or high-speed 2D graphics solution for photo or video editing or want to use a separate VGA monitor to extend your desktop, you should consider discrete graphics solutions instead.

Generally speaking, discrete graphics solutions have the following characteristics:

  • Dedicated memory. Depending upon the graphics chip used, the graphics subsystem might use discrete graphics chips or use memory embedded in the graphics chip itself. For example, the ATI Mobility Radeon 9600 is available in versions without built-in memory, or with 32MB, 64MB or 128MB of built-in memory and some versions of the nVidia GeForce4 Go also feature integrated memory.
  • Support for multiple displays (LCD panel and external monitor as separate displays) and TV-out.
  • Relatively fast DirectX 8.x/9.x support. The level of DirectX support depends upon the graphics chip (newer chips support newer DirectX versions).
  • Relatively fast performance because the graphics chip has its own onboard or dedicated memory, doesnt process anything other than graphics data, and in the case of nVidia or ATI solutions, has an advanced design based on desktop graphics chips.

To summarize: if you want the fastest graphics performance and most features, look for the latest ATI or nVidia mobile graphics chipsets in your laptop computer.

Comparing Desktop and Laptop Graphics Chips

Both nVidia and ATI base their graphics chips for laptop computers on their successful lines of desktop graphics chips. However, laptop graphics chips differ in several ways from their desktop parents:

  • Most laptop graphics chips have slower RAMDACs than their desktop counterparts. For example, the nVidia GeForce FX5200 has a 400MHz RAMDAC, while the nVidia GeForce Go5200 for laptops has a 350MHz RAMDAC. The RAMDAC converts digital signals into analog signals for display, and a slower RAMDAC leads to a slower 3D display. However, a slower RAMDAC also saves battery power.
  • Laptop graphics chips are usually based on mid-range or low-end rather than high-end desktop parts. For example, the top-of-the-line nVidia GeForce FX Go5700 is based on the mid-range nVidia GeForce FX 5700, and the top-of-the-line ATI Mobility Radeon 9700, despite the name, is based on the mid-range ATI Radeon 9600 XT.
  • Laptop graphics chips are usually optimized to use less power through low-power components and power-management features.

As a result, even the best laptop graphics chips are not capable of running 3D applications (games) at the same speed as the most expensive desktop graphics cards. However, since very few computer users can afford the best desktop graphics cards, a laptop equipped with a high-end discrete graphics chip from ATI or nVidia has a graphics solution comparable in most respects to whats installed in the vast majority of desktop computers.

Emerging Trends

As the body of this article makes clear, you no longer need to settle for low-performance integrated graphics when you buy a laptop computer. Both ATI and nVidias mobile graphics lines contain products which are adapted from their latest midrange desktop graphics chips.

However, the industry still lacks a real standard for interchangeable mobile graphics. One hopeful sign is the line of Alienware Area-51M gaming laptops, all of which feature user-upgradeable graphics modules based on ATI and nVidia laptop graphics chips. Although the technology is proprietary to Alienware, this is a significant development.

In the future, a portable offshoot of the new PCI Express standard called ExpressCard (formerly NewCard) might provide high-speed interchangeable graphics as well as other high-speed connectivity.

For Further Research

The official website for nVidias GeForce 4 Go series of discrete graphics chips is located at http://www.nvidia.com/page/geforce4go.html

The official website for nVidias GeForce FX Go series is located at http://www.nvidia.com/page/fx_mobile.html

The official website for ATIs Mobility series of discrete and integrated graphics chips is located at http://www.ati.com/products/mobile.html

The official website for the PCI Express specification is located at http://www.pcisig.com/specifications/pciexpress

The official website for Alienwares Area-51 line of products is located at http://www.alienware.com/system_pages/area-51m.aspx

Copyright©2004 Pearson Education. All rights reserved.

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