These are typical components used in PCs in mid-April. They range anywhere from about 400 to 600 Mhz and more. The chips are similar to the ones on desktops, but they must be specially engineered for a smaller case. Windows 98 is intended for everyday consumer or home office use, while 2000 is intended business users who need more stability or intend to run networks. A system may come with between 32 and 512 Megs.
More memory means the computer can keep more software and data running at one.
The low end on laptops can be rather extreme, resulting in a slow computer. Try for the middle of the range at least. Typically, any chip will work fine in business applications, unless one uses high-end multimedia applications. A 56K unit is standard everywhere. Until a new technology comes out that crams more data into a phone line, these will still be plentiful.