CPU Cabinate and Mother Board Form Factor

Computer Cases

full-tower >30 inch (76CM) 6 to 10 Drive Bays
Mid Tower 18 to 24 inch (45 to 60 CM) 2 to 4 Drive Bays mostly used
Mini Tower 12 to 18 inch (30 to 45 CM) 2 or 3 Drive Bays
Slim line case Monitor can be kept on it
Small Form Factor variety of sizes or shapes including shoe boxes, cubes, and book-sized PCs.

Motherboard Form Factor
Size of motherboard is also called form factor. Form factor identifies the size of the circuit board,the location of the slots as well as the location of the faceplate that comes out the back of the computer. The form factor also identifies the location of the holes that are used to mount the motherboard into the system case
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ATX Form Factor (Full ATX) 12″ x 9.6″ (30cm x 24cm) most commonly used
Mini ATX 11.2″ x 8.2″ (28cm x 21cm) less number of buses and memory slots
Micro ATX 9.6″ x 9.6″ (24cm x 24cm)
Flex ATX         9” x 7.5” (22.9 cm x 19.1 cm)
Mini ITX         6.7″ x 6.7″ (17cm x 17cm) still match the ATX hole positions
Em ITX 17 cm x 12 cm
Nano ITX 4.7″ x 4.7″ (12 cm x 12 cm)
Pico ITX         3.9” x 2.8” (10 cm X 7.2 cm)
Mobile ITX 2.4” x 2.4” (6 cm x 6 cm)
DTX Form Factor 8” x 9.6” (20,3 cm x 24,4 cm) backward compatible with ATX form factor
Mini DTX 8” x 6.7” (20,3 cm x 170 cm)

SSI form factor
SSI form factors were developed by SSI (Server System Infrastructure) forum, and are intended for dual or multi processor motherboards used in servers and or even workstations. SSI form factors were derived from ATX specification, so they have the same rear panel, IO connector area, and mounting holes. But, SSI form factors are larger than ATX, so SSI motherboards will not fit in cases designed for standard ATX.

Three SSI form factors are CEB (Compact Electronics Bay), EEB (Enterprise Electronics Bay), and MEB (Midrange Electronics Bay).

The smallest of them is SSI CEB, and the size is 12” x 10.5” (30,5 cm x 26,7cm).
SSI EEB (also called Extended ATX or E-ATX) and dimensions are 12” x 13” (30,5 cm x 33 cm)
The SSI MEB size is 16.2” x 13” (41,1 cm x 33 cm). It is longer in order to provide space for two additional CPU sockets. (4 CPU Socket rest of having 2)

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BTX Form Factor
There are a few main differences with the BTX form factor. Notice that the faceplate is on the opposite end. Another difference is that the hole positions are different. Also, the processor socket is slightly rotated so that it is at an angle to the system board.This rotation is to aid in the air㘀㄀ow across the processor to assist in cooling the processor. The BTX motherboard will only fit within a system case that is designed for a BTX motherboard.although there are system cases that are able to accommodate both the ATX and the BTX form factors.availability and variety of BTX-compatible components is limited.

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NLX Form Factor
NLX is an older form factor used for slimline desktop-style computers. NLX is an improvement over an even earlier LPX form factor. Notice that this motherboard has no expansion slots for the PCI or ISA bus. The NLX form factor is used in slim line cases that are very short.In order to accommodate expansion cards we use a tab on the edge of the motherboard. We insert a Riser Card on the end of the motherboard. Riser Card is then used for expansion cards, so that now expansion cards lay 㘀㄀at rather than being perpendicular to the motherboard. The riser card does not have built-in ports for audio, joystick, USB, network or modem.

Remember
When choosing a system case, other than considering the size of the computer that we want, the most important thing is to match the motherboard form factor with the form factor supported by the computer case. The most common system case type is the tower. Tower cases are: Full tower, Mid tower and Mini tower. Slim line cases are simply tower cases turned on their sideways. Small form factor or SFF cases are custom cases that are designed to minimize the spatial volume of a desktop
computer. The size of the motherboard is often called the Form Factor. The most common form factor for a motherboard is the ATX form factor. When considering the size of ATX we differentiate Full ATX, Mini ATX, Micro ATX, Flex ATX, Mini ITX, Em ITX, Nano ITX, Pico ITX, Mobile ITX. SSI CEB, SSI EEB, SSI MEB form factors are larger than ATX. When comparing with ATX, BTX form factor has the faceplate on the opposite side, hole positions are di漀椀erent and the processor socket is slightly rotated. The BTX motherboard will only 　㈀t within a computer case that is designed for a BTX motherboard. The NLX is an older style form factor that is not used very often anymore.

Hardware Kiddie.........