A hard drive is the electronic storage compartment, where software and data reside from day to day. The larger the drive, the better, but also the more expensive. Modem speeds are measured in baud, the number of symbol elements transmitted each second. Speeds range from 2400 to 28,800 baud. Higher-speed modems can also operate at the lower speeds.
Price directly reflects speed.
If the modem is the common 2400 baud, you will probably want to buy a separate, faster modem for any serious communications. Slower models do not save you much and will soon be obsolete. Usually this type has less expansion room inside. A minitower can free up even more desk space by sitting on the floor and offers the most extra expansion slots and bays for upgrades. Slots and Bays Expansion slots inside the computer allow you to plug in addition circuit boards such as internal modems, video cards, scanners and sound cards.