Sometimes referred to as the CPU, or central processing unit, the processor is the brains of the computer. It's the most important chip in a notebook, and it has power management features that extend battery life. Notebooks use a variety of processor types depending on their focus. The chart below shows all of the laptop processors currently available from AMD and Intel; in practice, most manufacturers offer laptop configurations using only a handful of the most recent chips.

Note that this chart shows only the relative performance and battery life of each processor within the product lines of AMD and Intel. The rankings are not based on independent test results, and the actual performance and battery life of a laptop will depend on many factors, including the display, the size of the battery, and the optimizations made by the manufacturer. The only way to accurately gauge performance and battery life is through hands-on reviews based on objective labs tests.

Processor	Notebook type	Performance	Battery life	Price
AMD Turion 64 X2 Dual Core	All types
Intel Core 2 Extreme	High-end gaming machines
Intel Core 2 Duo	All types
Intel Pentium Dual Core	Budget portables
Intel Pentium M	Sub-notebooks; budget portables
Intel Celeron M	Sub-notebooks
Intel A100 and A110	Sub-notebooks
VIA chips	Sub-notebooks

Every computer comes with a certain amount of physical memory, usually referred to as main memory or RAM (random-access memory). Computers store currently running applications and data in this area. To find out how much memory you'll need, take into account your operating system and the applications you plan to use. A general rule of thumb: You'll want 2GB for Windows Vista or 1GB for Mac OS X.

If you're planning to hang onto your notebook for a long time, look for a laptop with easy-to-access memory slots, as memory is typically one of the first specs you'll want to upgrade.

Unlike traditional desktop CRT (cathode-ray tube) monitors, notebooks ship with thin, liquid-crystal displays (LCDs). Notebook LCDs range in size from 10.6 inches (diagonal) to 20 inches; display size is a key factor in the laptop's overall weight. For comfortable viewing at the preferred Windows resolution of 1,024 x 768, most people like 14.1-inch or larger LCDs.

The ultraportable Fujitsu LifeBook P1610 (left) has one of the smallest screens--just 8.9 inches--in order to accommodate its featherlight 1kg weight. The giant 20-inch Dell XPS M2010 (right), on the other hand, has the biggest notebook screen we've ever seen.

Notebook LCDs once varied widely in brightness, color, and sharpness, but today you'll find much better quality across the board. Unfortunately, when it comes to LCDs, the specs reveal little about actual picture quality. So if you're picky about screens, compare some at your local dealer.