Encasements Unlike motherboard form factors, there are no standardized specifications for computer cases. They come in a plethora of sizes, shapes and colors in order to accommodate most any taste from a conservative business setting to the bedroom of a teen addicted to gaming. From an engineering standpoint the case must perform two tasks. First, it must be capable of holding all the system components needed now and in the foreseeable future for a case is reusable from one computer generation to the next. Second, the case must be capable of venting the heat generated by the system. Heat is the single greatest contributor to component failure. The materials used to make passive components such as capacitors, inductors, and resistors dry out; and active components like APUs, CPU, voltage regulators, and memory chips are subject to thermal runaway, a condition in integrated circuits where boundary layers break down and excessive current flow causes damage. The four basic encasement sizes are SFF, Mini-Tower, Mid-Tower, and Full Tower. The table below provides the basic component handling capabilities of each case type. Other considerations are the gauge of the metal parts, the quality of the plastic parts, noise absorbing materials if any (fan noise), and air flow through the case. SFF Mini Tower Mid Tower Full Tower Motherboards Mini-ITX Mini-ITX Mini-ITX Mini-ITX Micro-ATX Micro-ATX Micro-ATX ATX ATX EATX 5.25" Drive Bays 1 1 to 2 2 to 5 3 to 6 3.5" Drive Bays 1 to 3 4 to 6 6 To 8 6 to 13 2.5" Drive Bays 0 to 4 0 to 4 0 to 10 0 to 11 Expansion Slots 1 2 to 4 7 to 8 7 to 10 Graphics Cards 1 1 to 2 2 to 3 3 to 4 Case Fans 1 to 3 2 to 4 3 to 9 5 to 10