Table 1-5 Motherboard Form Factors

Table 1-5 Motherboard Form Factors - student2.ru

Form Factor	Dimensions (mm)	Details and Descriptions

ATX	305x244	The basic motherboard.

Micro ATX	244x244	A smaller square version ATX motherboard with
		fewer expansion slots.

ITX	215x191	Designed to be used with completely integrated
		devices. Not widely used, but inspired smaller
		mini-ITX design.

		Chapter 1: Hardware 17


Form Factor	Dimensions (mm)	Details and Descriptions

Mini-ITX	170x170	Designed to be used with completely integrated
		devices. Popular choice for Home Theater PCs and
		servers. Some feature a single PCIe x16 expansion
		slot.

BTX	325x266	Used by some retail and a few custom-built sys-
		tems; features integrated thermal module for cool-
		ing processor and memory modules.

NLX	254x228	Integrated AGP, NIC, and USB support. Now obso-
		lete.

LPX	330x229	Expansion cards are mounted on riser cards that
		can run parallel to motherboard or at a right angle
		and can, therefore, fit in to a smaller case. Now
		obsolete.

Expansion Cards and Slots

Expansion cards (also known as adapter cards) allow the motherboard to connect and control countless devices. Expansion cards connect to the motherboard via expansion slots. Adapter cards can also share some of the processing responsibility, which lightens the load on the CPU. Table 1-6 describes the standard expansion slots.

Table 1-6 Expansion Slots

Table 1-5 Motherboard Form Factors - student2.ru

Adapter Card / Bus Name Details and Descriptions

Bus Width

Table 1-5 Motherboard Form Factors - student2.ru

PCIe	x1
	x4
	x8
	x16

Supports full duplex (sends/receives data simultaneous-ly). Throughput is 250MBps per lane (PCIe version 1) or 500MBps per lane (PCIe version 2). Each lane is x1. Four lanes = x4. Eight lanes = x8. Sixteen lanes = x16.

Table 1-5 Motherboard Form Factors - student2.ru

Mini-PCIe	x1	1.5V, 3.3V version of PCIe x1 for laptops and note-
		books; mainly used for Wi-Fi

PCI		Current standard, 32 bit and 64 bit, shorter than ISA;
		usually white; 64-bit version has three inline connectors

		Two inline connectors; usually white

18 CompTIA A+ Quick Reference

Table 1-5 Motherboard Form Factors - student2.ru

Table 1-6 Continued

Table 1-5 Motherboard Form Factors - student2.ru

Adapter Card /	Bus Name	Details and Descriptions
Bus Width

Mini-PCI		33MHz, 3.3V, used in notebook and laptop computers
		for Wi-Fi and communications

PCI-X	64-bit	Same slot design as 64-bit PCI
		133MHz (version 1.0), 266 and 533MHz (version 2.0)

AGP version 1.0		Dedicated graphics card slot, inset from rear of mother-
(AGP 1x, 2x)		board; runs at 66MHz
		1x throughput 266MBps
		2x throughput 533MBps
		3.3V slot

AGP version 2.0		1066MBps throughput
(AGP 4x)		1.5V slot


AGP version 3.0		2133MBps throughput
(AGP 8x)		0.8V and 1.5V slot (cards backward compatible with

		AGP v2.0)

AGP Pro		Provides additional power; speeds vary

EISA		Old technology, 32-bit version of ISA; backward com-
		patible with ISA

ISA		Black

		Common in older PCs

Figure 1-8 shows the relative size and form factors of the common expansion slots. You should be able to identify these during your CompTIA A+ Certification exams.

Chapter 1: Hardware 19

Table 1-5 Motherboard Form Factors - student2.ru