Asus posted today an article that explains the need of having a dedicated graphics card at your laptop...

What is a Dedicated Graphics Engine?

A dedicated graphics engine ("DGE" or "discrete graphics") is a dedicated graphics processing chip designed to improve graphics function on your notebook or PC. It does so by taking the chores of reading from memory and performing all screen updates away from your laptop's CPU, leaving the processor free to purely handle calculations. Today's dedicated graphics engines also process lighting, shading and 3D graphics, decode video accelerators, and perform motion compensation. A DGE has its own integrated memory and does not need the CPU to access information in the main memory. Because they are hardware, DGEs will of course add to the cost of your machine. Most people find the investment well worth it.

How Will a DGE Affect a Laptop's Performance?

In laptops without a DGE, the CPU performs all of the above functions itself, which is a huge burden. Today's higher resolution screens require a tremendous amount of work, and CPUs without dedicated graphics engines can easily become overloaded. When they are overloaded, the performance of applications as simple as word processing can noticeably suffer from pauses and delays. More demanding applications like 3D games are even more seriously affected.

Without Dedicated Graphics Engine With Dedicated Graphics Engine

When a DGE is added to the system, the results of the vast improvement in data processing capacity are very plain to see. The frame rate in such a system increases tremendously, changing slow, jerky 3D in games into something more smooth and natural. Video playback quality improves significantly, and less demanding applications like word processing work without annoying pauses.

Does Everyone Need a DGE?

A dedicated graphics engine is suitable for every type of user. For those who use their laptops merely for office applications and light web surfing a DGE is not critical, although the difference in performance will still be noticeable. Anyone who will be gaming or viewing any kind of 3D video requires a DGE. Once the need for a DGE is established, the decision becomes "which one to get?" Higher power DGEs with 512MB or 256MB of memory (like those in ASUS' F3Jm, W3J or A8Jm) will of course give users the best performance for more demanding applications like the latest games or video editing software, and will keep their laptops current for a long time to come. But more popular DGEs with 128MB of memory (like in ASUS' W7J) will provide significant benefits in graphics performance for all but the most demanding applications.

Considering the benefits a dedicated graphics engine adds, for most people this choice is a no-brainer as long as they understand the facts. Look for promotions this month on ASUS laptops featuring dedicated graphics engines.