Memory is used for quick access from the hard drive to the CPU, and back. Memory, also called RAM (Random Access Memory) can be thought of as a very small, very fast hard drive. Notebook configurations for memory usually range anywhere from 512 - 4096 Megabytes. The measurement of RAM is the same measurement as a hard drive, or file size.

The more memory your machine has, the more programs can be opened and running at the same time without having to access the comparatively slower hard drive for more information. More memory will cause Windows and other programs to load, and execute more efficiently.

Memory also comes in different speeds. Some various speeds are PC100, PC133, PC2100, etc. These speeds represent how fast the memory runs at. The faster the memory, the faster information can be copied to and from the device. PC100 RAM runs at 100 Mhz, using the same speed measurements as the CPU. PC2700, however runs at 333 Mhz, because of a different naming convention. Memory also has a newer technology called DDR2, or Double Data Rate 2. A 128 MB stick of memory with DDR2 runs four times the number of reads and writes as a 128 MB stick of non-DDR memory.