Lesson 2: The
Motherboard
Time Estimate
30 minutes
Overview
The motherboard, also called the "main board," is the core of your PC
system. Bolts secure it tightly inside the case, and it contains all of
the key processing parts, such as the CPU, memory, cache, expansion
busses, chipset, etc. The motherboard's characteristics almost entirely
define your system's performance, and you'll find that a motherboard is
the most important PC part (and the least expensive).
Because the motherboard contains most of the processing parts,
replacing it yields the greatest performance improvement for your money. Also,
motherboards quickly drop in price, so unless you need the latest
model, you can buy a recent model for relatively short money. This makes
motherboard upgrades economical, although labor-intensive.
Upgrades usually separate into two levels:
Add-ons involve changing the parts attached to the motherboard, such as
the CPU, memory single in-line memory modules (SIMMs) or dual in-line
memory modules (DIMMs), or cache. These parts can improve system
operation even without replacing the motherboard.
Replacement involves replacing the physical circuit board.
Busses
Motherboards rarely offer all of the features your computer needs.
Fortunately, you can add devices to the motherboard by plugging them into
expansion slots, or busses. There are four different expansion busses
that you should be familiar with: ISA, PCI, AGP, and AMR.
ISA
The classic Industry Standard Architecture (ISA) 16-bit expansion bus.
Although this bus is older than other busses, you can find plenty of
16-bit cards, such as modems, Small Computer System Interface (SCSI)
adapters, and sound cards. Current PC specifications call for the complete
elimination of ISA slots. The latest motherboards often contain one
ISA slot, to give users a little more time before replacing their ISA
add-on cards with PCI cards. The motherboard you select should have one
or two ISA slots, unless you do not have any ISA cards. In this case,
select a motherboard with no ISA slots.
Note: Avoid buying ISA add-on cards. The PCI bus offers better
performance, Plug-and-Play support, and versatility.
PCI
The Peripheral Component Interconnect (PCI) bus originally evolved as a
high-speed answer to the now obsolete Video Local Bus (VLB), which was
geared toward video systems. The PCI bus supports general devices,
such as video boards and drive controllers, the most common PCI devices.
Now, there are modems, sound cards, and many other peripherals that use
the PCI bus. PCI performs excellently with superior data throughput;
its fixed 30/33MHz clock speed makes it far more stable than VLB. It is
best to find a motherboard with four to six PCI bus slots.
AGP
The Accelerated Graphics Port (AGP) recently appeared with Pentium II
and "Super 7" motherboards. Essentially a 66MHz PCI bus, AGP uses the
higher bus speed and several hardware tactics to dramatically accelerate
data throughput. The AGP also accesses main system RAM for storing
graphics textures, making video RAM less critical. You should purchase an
AGP, or any video card, with as much on board memory as your budget
will allow. Since most PCs only use AGP for video adapters, it is not
necessary on your motherboard; a PCI video adapter works fine in its
place. For top video performance under Windows 98/SE, consider selecting a
motherboard with one AGP slot.
AMR
The new Audio Modem Riser (AMR) specification is a hardware scaleable
motherboard riser board and interface, which supports low-cost audio and
modem devices. Unless low cost is your highest priority, you can use a
PCI-based modem or sound card for best performance, and ignore the AMR.
Central Processing Unit (CPU)
The CPU is the main processing component on your system; it processes
all program instructions and data. The faster and more powerful a CPU
is, the more performance your computer will offer. Keep in mind, a CPU
operates in conjunction with other motherboard elements. So a new CPU
installed in an older motherboard may not offer the same performance as
one installed in a state-of-the-art motherboard. When selecting a CPU,
make sure that your motherboard can support it.
You can select from many different types of CPUs depending on the age
and capabilities of your motherboard. Read the below for some leading
candidates:
|
Pentium |
| Pentium Pro |
| Pentium MMX |
| Pentium II |
| Pentium II "Celeron" |
| Pentium III |
| Pentium II and III "Xeon" |
| Pentium IV |
| Am5x86 |
| K5 series |
| K6 series |
| K6-2 with 3DNow |
| AMD K6-III |
| AMD Athlon |
| 6x86 series |
| MediaGX |
| 6x86MX (MII) |
| VIA Cyrix III |
The CPU connection type often classifies motherboards. There are now
four typical CPU connections: socket 7, slot 1 and slot 2, socket 370,
and slot A.
Socket 7
Socket 7 motherboards support most classic Pentium-type processors
(i.e., Intel Pentium, Intel Pentium MMX, AMD K5, AMD K6, AMD K6-2, Cyrix
MII, IBM 6x86, and IBM 6x86MX). By setting the proper clock speed and
multiplier, a Socket 7 motherboard supports a variety of Pentium-type
CPUs without making any other hardware changes. This versatility makes
sockets important and extends the working life of current PCs by
providing an upgrade path for CPUs.
Slot 1 and slot 2
In contrast, Intel has switched its processor packaging to a
"cartridge-type" arrangement. Slot 1 motherboards support ordinary Pentium II,
Pentium III and Intel Celeron processors. Slot 2 motherboards, intended
mainly for high-end server systems, support Pentium II Xeon processors.
Slot 1-type processors are described as Slot 1 or Single Edge Processor
Package (SEPP). Intel is developing an adapter that allows Slot 1
motherboards to use a Socket 370 Celeron, referred to as a "Slotket".
Socket 370
Intel recognized a need for a "Socket" Celeron to meet various
manufacturing and consumer demands and introduced the "Socket 370" package
style, the Plastic Pin Grid Array (1PPGA). Many Celerons are available
through both the cartridge and the Socket 370 packages.
Slot A
Advanced Macro Devices' (AMD) designed their most recent offering, the
Athlon, in the cartridge style dubbed "Slot A." This slot is similar
to the Intel Slot 1, with the exception of the placement key, which is
180 degrees from Slot 1's key. This means the Athlon will not fit on a
Slot 1 motherboard.
Heat Sink/CPU Fan
CPU's heat up quickly. So you don't ruin your CPU investment, you need
to keep the CPU cool. Use a heat sink/CPU fan that mounts directly to
the CPU. The heat sink is a metal radiator that carries heat away from
the CPU. The fan, built into the heat sink, forces air through the
heat sink for efficient cooling. You can buy a heat sink/fan when you buy
the CPU.
CPU Manufacturers
Random Access Memory (RAM)
Computers use RAM to hold program data and instructions while the CPU
executes them, requiring RAM on the motherboard. Older computers often
incorporated one or two megabytes (MB) of RAM on the motherboard, then
allowed you to add more memory in the form of SIMMs. Today, all
motherboards use SIMMs or DIMMs exclusively, making it much easier to replace
defective memory without replacing the entire motherboard. You choose
the starting amount of RAM when you select the motherboard.
SDRAM
Synchronous Dynamic Random Access Memory (SDRAM) is enhanced memory
that allows data to transfer at any point in the system's clock cycle,
rather than at set intervals, creating faster memory performance. SDRAM
also move (burst) large amounts of data to and from memory. Recent
motherboard chipset versions support SDRAM. PC100 RAM is a variation of
SDRAM. With newer motherboards using a bus speed of 100MHz, RAM timing
becomes critical. PC100 RAM is SDRAM certified to run properly on
100MHz motherboards. If you do not select PC100 RAM, make sure that your
SDRAM works at 100MHz. PC133 RAM is available for motherboards using a
bus speed of 133MHz. Review some of the current memory technologies
below:
RDRAM
Now on hold, In 1997 Intel hoped Rambus DRAM (RDRAM), or "Rambus" would
set the standard for memory technology supported by their 800 series
chipsets. Rambus is an extremely high-speed type of memory capable of
bursts as fast as two nanoseconds per byte. Rambus can transfer in
excess of 533MHz, and can handle multiple Rambus Channels, which can achieve
transfer rates of up to 533MB a second each. If you run four channels
(the maximum supported for one controller), you can receive transfer
rates over two gigabytes per second.
DDR DRAM
Double Data Rate DRAM (DDR RAM), also known as DDR-SDRAM, DDR RAM
nearly equals Rambus performance. Like many of its memory predecessors, DDR
RAM was first developed for use on video cards. Double Data Rate
transfers allow data to move on both the rising and the falling edges of a
clock cycle. This means that PC133 DDR memory will effectively provide
266MHz performance on today's 133MHz system buses. DRAM technology
drives the DDR, effectively lowing costs.
Memory Manufacturers
Basic Input/Output System (BIOS)
The BIOS chip is a form of permanent memory that holds instructions for
the motherboard to communicate with the operating system. In short,
BIOS "drives" motherboard hardware and supports features, such as
plug-and-play and power conservation. Because BIOS comes with the
motherboard, you don't need to select it separately, unless you choose an
upgrade.
Generally, upgrade BIOS if it would improve your hardware, or if a
clear problem prevents an important feature or function from working. For
example, you decide to upgrade the motherboard's video system by adding
a new video board and you need to disable the motherboard video system.
If your motherboard has a poor design, a flaw in the BIOS prevents you
from fully disabling the video, so a BIOS upgrade might fix this
problem.
You can reprogram virtually all BIOS chips, with "flash" ROM chips, "on
the fly" without replacing them. As long as you do not experience
problems, and your current BIOS supports all of your components, there is
usually no reason to flash update your BIOS. If you do experience
problems, or if you plan to upgrade a component, check the motherboard or
system manufacturer's Web site for a BIOS update. You will probably see
the list of the update's added features along with the BIOS update
file's version and release date.
BIOS Makers
Chipset
Chipsets are a set of two or three highly integrated chips that work
together to provide the highest possible performance for motherboards and
CPUs. In fact, most chipsets are specific to certain CPU families.
When shopping for a motherboard, you will may encounter the following
current chipsets:
For Pentium motherboards:
- Intel 430FX chipset (Triton)
- Intel 430HX chipset (Triton 2)
- Intel 430VX chipset
- Intel 430TX chipset
- Intel 430MX chipset
- AMD 640
- VIA Apollo VP-1 chipset
- VIA Apollo VP-2 chipset
- SIS 5571 chipset
- Opti Viper-M chipset
For PentiumPro motherboards:
- Intel 440FX chipset (Natoma)
- Intel 450GX/KX chipset (Orion)
- VIA 680 VP Apollo P6
For Pentium II/III and Celeron motherboards (Intel CPUs):
- Intel 440LX chipset (classic Pentium II and basic Celeron support)
- Intel 440BX chipset (current AGP/100MHz motherboard support for
Pentium II and III)
- Intel i810 chipset (for low-end Pentium II/III and
Celeron-integrated 2D/3D AGP graphics)
- Intel 440EX chipset (designed to optimize Celeron systems with AGP
bus)
- Intel 440ZX chipset (supports Celeron systems at 100MHz and AGP
bus)
- Intel 440ZX-66 chipset (supports low-end Celeron systems at 66MHz
and AGP bus)
- Intel 450NX chipset (provides PCI bus support for Xeon processors)
- Intel 440GX chipset (provides AGP bus support for Xeon processors)
- Intel 810E (Updated 810 with support for 66/133MHz system bus
speeds)
- Intel 820 (Pentium II/III, AGP 4X, ATA/66, supports both Rambus and
PC133 SDRAM memory)
- Intel 840 (Pentium III/Xeon, AGP 4X, ATA/66, supports both Rambus
and PC133 SDRAM memory)
- ALi Aladdin Pro II (AGP bus and Pentium II support at 66/100MHz)
- ALi Aladdin Pro IV (AGP 4X and support for 66/100MHz Pentium II,
III and Celeron)
- ALi Aladdin TNT2 (Integrated AGP video, 66/100MHz bus with support
for Pentium II, III and Celeron)
- VIA Apollo Pro (Slot 1 Intel Pentium II and Socket 8 Intel Pentium
Pro processors, AGP bus)
- VIA Apollo Pro Plus (Pentium II/III and Celeron with AGP bus)
- VIA Apollo Pro 133 (Pentium II/III and Celeron, AGP and PC133 bus)
- VIA Apollo Pro 133A (Pentium II/III and Celeron, VIA Cyrix III, AGP
4X, ATA/66, PC133 bus)
- VIA Apollo PM601 (Pentium II/III and Celeron, VIA Cyrix III,
Integrated AGP 2X, ATA/66, PC133 bus)
For Super 7 motherboards (AMD/Cyrix CPUs):
- ALi Aladdin V (AGP chipset with 66/100MHz bus support for M1, M2,
K5, K6, and K6-2)
- ALi Aladdin 7 (AGP chipset with 66/1xxMHz bus support for Socket 7
and Slot 1/Socket 370)
- ALi Aladdin IV and IV Pro (PCI chipset with 50/83.3MHz bus support
for 586 type CPUs)
- VIA Apollo MVP3 (AGP chipset with 66/100MHz bus support for M1, M2,
K5, K6, and K6-2)
- VIA Apollo VP3 (AGP chipset with 66 MHz bus for Pentium/MMX, K5,
K6, 6x86, and 6x86MX)
- VIA Apollo MVP4 (VP3 with integrated AGP graphics controller)
For Slot A motherboards (AMD Athlon)
- AMD 750
- VIA KX133 VT8371 (AGP 4x, PC133, 200MHz FSB, ATA-66)
You will come across other chipsets, the following are the most
popular:
Chipset Makers
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