I've heard from many friends that the highest rate of success in upgrading laptop graphics cards occurs in Dell laptops. If you have another brand of laptop, there is a very high chance the graphics are not upgradeable. So if you have a Dell laptop, lucky you - you probably can do a nice graphics card upgrade.
 

Dell laptops are likely to have upgradeable graphics cards

Before you can decide which is the best graphics card for your laptop, you need to understand the distinguishing characteristics of laptop graphics cards.

One of the first things you need to know is the difference between integrated graphics and dedicated graphics. Integrated graphics parts are a part of the motherboard in your laptop computer.

Dedicated graphics are part of a distinct and separate graphics card in your laptop. Dedicated graphics will always outperform integrated graphics in varying degrees.

A dedicated laptop graphics card from nVidia

My personal feel is that if you want to play the latest games on your laptop, you better get a dedicated graphics card.

As usual, there are buzzwords when it comes to graphics card technologies. nVidia has a TurboCache feature which is implemented in hardware, i.e. on the nVidia graphics chips themselves. This allows TurboCache nVidia chips to interface with system memory very quickly.

ATI's answer to nVidia is HyperMemory, which is implemented entirely in software. It is available for virtually all ATI hardware. As it is implemented in software, I'd expect that HyperMemory is slower than TurboCache.

If you're serious about upgrading your laptop graphics card, it also pays to understand some standards for laptop graphics card used in the industry. There are currently two main ones in the market: ATI's AXIOM standard and nVidia's MXM standard. MXM parts are further broken down into three types, with Type I parts being the smallest.

To be honest, these standards are still in their infancy. It has been difficult for the laptop graphics market to agree on a common standard (unlike USB ports). The reason is that unlike a desktop PC, laptops have to worry about thermal issues and power consumption.

So different manufacturers have extremely different ways to tackling these issues in their designs. The result is that in terms of graphics cards, the industry still has a long way to go in terms of standards.

Let's take a look at the more popular integrated laptop graphics cards in the market. They are as follows:

• Intel Graphics Media Accelerator (GMA) 900/950
• ATI Radeon Xpress 200M / 1100 / 1150
• nVidia GeForce Go 6100 / 6150
• S3 Unichrome

The more popular dedicated laptop graphics cards are listed below:

Low-end cards

• ATI Mobility Radeon X600
• nVidia GeForce Go 6200/6400
• nVidia GeForce Go 7200/7300

Mid-range cards

• ATI Mobility Radeon X1400
• nVidia GeForce Go 7400
• nVidia GeForce Go 6600

Performance cards

• ATI Mobility Radeon X1800
• nVidia GeForce Go 7900 GS
• nVidia GeForce Go 7800

If you've been reading up about laptop graphics cards, you might have come across this term called SLI. The technology allows you to use two dedicated graphics cards in your laptop to boost 3D performance.
 

The nVidia SLI logo
 

Now, SLI is an nVidia technology, so it only appears in the nVidia Go 7800 and 7900 series. ATI has a similar technology for desktops called CrossFire - but it is not yet implemented for laptops.

My personal feeling about SLI is that it is only for super hardcore gamers. Note that SLI performance increase is never linear. This means that having two graphics processors will NOT double your graphics performance. The increase is probably slightly less than that.