Abit IT5E User Manual
Table of Contents
Chapter 1 Introduction of IT5 Series Features
(1) IT5V..................................................................................1-2
l Specifications ................................................................1-2
l Layout diagram..............................................................1-4
l System block diagram....................................................1-5
(2) IT5H..................................................................................1-6
l Specifications ................................................................1-6
l Layout diagram..............................................................1-8
l System block diagram....................................................1-9
Chapter 2 Installing the Mainboard
(1) Standard External Connectors............................................2-3
(2) Jumpers and Switches.......................................................2-10
(3) Presentation and Installation of the CPU...........................2-11
(4) Installing Pipeline Burst SRAM........................................2-14
(5) Installing System Memory <DRAM Memory>..................2-15
Chapter 3 Introduction to BIOS
(1) CPU setup <CPU SOFT MENU™>.....................................3-4
(2) Standard CMOS Setup Menu...........................................3-10
(3) BIOS Features Setup Menu ..............................................3-12
(4) Chipset Features Setup Menu...........................................3-18
(5) Power Management Setup Menu......................................3-20
(6) PCI & Onboard I/O Setup................................................3-24
(7) Load BIOS Defaults .........................................................3-30
(8) Load Setup Defaults.........................................................3-30
(9) Password Setting..............................................................3-31
(10) IDE HDD Auto Detection..............................................3-32
Part Number:MN-090-B21-71 Rev:1.02
Appendix A Quick Installation
Appendix B Intel Pentium CPUs
Appendix C AMD-K5 CPUs
Appendix D Cyrix 6x86 CPUs
Appendix E General Discussion about HDD Installation
Appendix F Technical Support
Appendix G Flash BIOS User Instructions
Introduction of IT5 Series Features 1-1
Chapter 1 Introduction of IT5
Series Features
The IT5 series has been especially designed for File server,
Workstation and Professional users. It can support a wide range of
processors, including all Intel CPUs (P54C) and Intel CPUs with MMX
(P55C), as well as all AMD-K5 and Cyrix 6x86/6x86L CPUs. It also takes
into account, as much as possible, all future CPUs.
This series uses SOFT MENU™ technology, which means that all the
parameters can be configured without using DIP switches or jumpers.
The configuration is entirely achieved through a “Soft Switch” that allows
the user to set CPU speed and operating voltage with ease.
The IT5 series uses Intel 430VX and 430HX series chipsets, and has
256K or 512K Level-2 Pipeline Burst SRAM on board. It also provides
an extension slot allowing the user to upgrade Pipeline Burst SRAM to
512K.
Two 168-pin DIMM slots and four 72-pin SIMM slots meet the
requirements for all memory configurations required by high level
computing. The 168-pin DIMM slots support traditional Fast Page and
EDO DRAM as a memory standard for next generation 64-bit systems.
The two 168-pin DIMM slots have been reserved to meet requirements for
both present and future upgrades.
This series also provides two Universal Serial Bus (USB) ports and
meets the Concurrent PCI Rev. 2.1 standard. It also supports IDE
interface for Fast HDD (Mode 0~4), as well as IDE Bus Master. These
features also meet present and future interface standards and needs.
System BIOS features include Plug-and-Play (PnP), Advanced Power
Management (APM), the newest Desktop Management Interface (DMI), as
well as IT5’s unique CPU operating frequency and voltage setup feature in
order to meet modern computing demands.
1-2 Chapter 1
(1) IT5V
l
Specifications:
1. CPU frequency and voltage setup with CPU “SOFT MENU™”
l Setup of the mainboard’s frequency and voltage without DIP
Switches or Jumpers.
l Modification of CPU operating voltage and frequency through
software configuration.
l Modification of CPU operating voltage and frequency directly
on screen.
2. Uses ZIF CPU Socket 7 for easy CPU installation
l Three voltage regulator/cooling plate sets for a more stable
CPU operating environment
l Supports Intel Pentium® CPUs: 75MHz to 200MHz and
P55C CPUs with MMX
l Supports all AMD sixth generation AMD-K5™ CPUs: 75MHz
to 100MHz
l Supports all Cyrix sixth generation 6x86™ CPUs: P120+,
P133+, P150+, P166+, P200+
l Reserved circuitry supports future sixth generation CPUs
3. Chipset
l Intel 430VX chipset
l Supports standard version PCI 2.1
4. L2 Cache Memory
l 256K or 512K of cache memory (Pipeline Burst SRAM)
l Cache memory upgradeable to 512K
5. System DRAM
l Four 72-pin SIMM sockets: support FP and EDO DRAM
l Two 168-pin DIMM sockets: support FP, EDO and
Synchronous DRAM (SDRAM)
l DIMM sockets use PC modules (3.3V Unbuffered DRAM)
l Up to 128MB memory configuration possible
Introduction of IT5 Series Features 1-3
6. System BIOS
l AWARD BIOS
l Supports Plug-and-Play (PnP)
l Supports Advanced Power Management (APM)
l Supports Desktop Management Interface (DMI)
7. Multi I/O features
l Two Universal Serial Bus (USB) ports
l Four fast IDE channels (PIO mode 0~4 and Bus Master)
l One EPP/ECP parallel port and one 16550 serial port
l Two floppy disk drive connectors (FDD) (360K, 720K, 1.2M,
1.44M and 2.88M)
8. Other features
l Standard AT architecture dimensions
l Four ISA bus slots and four PCI bus slots
l Supports 3-MODE for a special Japanese floppy disk drive
l Supports two bootable hard disks--able to run two different
operating systems
Note: All brand names and trademarks are the property of their respective owners.
1-4 Chapter 1
l Layout diagram
Fig 1-1 Layout diagram
Introduction of IT5 Series Features 1-5
l System block diagram
Pentium Processor
Host BUS
CACHE
(SRAM)
PCI BUS
CD ROM &
Hard Disk
Second
Level Cache
TAG
Fast
IDE
Ctrl
Tag Ctrl
TIO[0..7]
PIIX3
3.3V
TVX
Addr
Ctrl
Plink
Address/Data
USB
Universal Serial Bus
USB
Main
Memory
(DRAM)
TXD Ctrl
Control
Control
Address
Data
Data
TDX
PCI Device(s)
ISA Device(s)
ISA BUS
Serial
ALi
M5123
Fig. 1-2 System block diagram
LPT
FDC
1-6 Chapter 1
(2) IT5H
l
Specifications:
1. CPU frequency and voltage configuration with CPU “SOFT
MENU™”
l Setup of the mainboard’s frequency and voltage without DIP
Switches or Jumpers.
l Modification of CPU operating voltage and frequency through
software configuration.
l Modification of CPU operating voltage and frequency directly
on screen.
2. Uses ZIF CPU Socket 7 for easy CPU installation
l Three voltage regulator/cooling plate sets for a more stable
CPU operating environment
l Supports Intel Pentium® CPUs: 75MHz to 200MHz and P55C
CPUs with MMX
l Supports all AMD sixth generation AMD-K5™ CPUs: 75MHz
to 166MHz, AMD-K6™ CPUs: 200MHz and 233MHz
l Supports all Cyrix sixth generation 6x86™ CPUs: P120+, P133+,
P150+, P166+
l Reserved circuitry supports future sixth generation CPUs
3. Chipset
l Intel 430 HX chipset
l Supports standard version PCI 2.1
4. L2 Cache Memory
l 256K or 512K of cache memory (Pipeline Burst SRAM)
l Cache memory upgradeable to 512K
5. System DRAM
l Four 72-pin SIMM sockets: support FP and EDO DRAM
l Two 168-pin DIMM sockets: support FP, EDO
l DIMM sockets use PC modules (3.3V Unbuffered DRAM)
l Supports error check and correction (ECC) function
l Up to 512MB memory configuration possible
6. System BIOS
l AWARD BIOS
Introduction of IT5 Series Features 1-7
l Supports Plug-and-Play (PnP)
l Supports Advanced Power Management (APM)
l Supports Desktop Management Interface (DMI)
7. Multi I/O features
l Two Universal Serial Bus (USB) ports
l Four fast IDE channels (PIO mode 0~4 and Bus Master)
l One EPP/ECP parallel port and one 16550 serial port
l Two floppy disk drive connectors (FDD) (360K, 720K, 1.2M,
1.44M and 2.88M)
8. Other features
l Standard AT architecture dimensions
l Four ISA bus slots and four PCI bus slots
l Supports 3-MODE for a special Japanese floppy disk drive
l Supports two bootable hard disks--able to run two different
operating systems
Note: All brand names and trademarks are the property of their respective owners.
1-8 Chapter 1
l Layout diagram
Fig. 1-3 Layout diagram
Introduction of IT5 Series Features 1-9
l System block diagram
Pentium Processor
Host BUS
CACHE
(SRAM)
PCI BUS
CD ROM &
Hard Disk
Second
Level Cache
TAG
Fast
IDE
Ctrl
Tag Ctrl
TIO[0..7]
TIO[8..10]
PIIX3
3.3V
TXC
Data
Address/Data
USB
Universal Serial Bus
Addr
Ctrl
ECC
Control
USB
Control
Address
Data
Main
Memory
(DRAM)
PCI Device(s)
ISA Device(s)
ISA BUS
Serial
ALi
M5123
LPT
FDC
Fig. 1-4 System block diagram
1-10 Chapter 1
Installing the Mainboard 2-1
Chapter 2 Installing the
Mainboard
This mainboard series not only provides all standard equipment for
classic personal computers, but also provides great flexibility for meeting
future upgrade demands. This chapter will introduce step by step all the
standard equipment and will also present, as completely as possible future
upgrade capabilities. This mainboard is able to support all Intel Pentium
including P55C with MMX, Cyrix 6x86, 6x86L and AMD-K5 processors
now on the market. (For details, see specifications in Chapter 1.)
However, we cannot guarantee that the description given in this manual on
the circuitry of your mainboard will work for processors not listed in
Chapter 1. For example, the operating voltage of Cyrix’s next generation
CPUs is unknown at the present time. Thus we were not able to include
these specifications in your motherboard. We will supply further
information about CPU support when new CPUs arrive on the market.
This chapter is organized according the following features:
ΠStandard external connectors
• Jumpers and switches
Ž Installing the CPU--steps for installing Intel, Cyrix and AMD
processors.
• Installing cache memory--If you don’t want to upgrade the cache
memory you can skip this chapter.
• Installing the system memory.
NNNN
Before proceeding with the installation
Before installing the mainboard please be sure to turn off or disconnect
the power supply unit. Before making any modifications to the hardware
configuration of the mainboard, the power supply to any areas of the
mainboard you plan to modify should be turned off to avoid unnecessary
damage to the hardware.
2-2 Chapter 2
&
User friendly instructions
Our objective is to enable the novice computer user to perform the
installation by themselves. We have attempted to write this document in
a very clear, concise and descriptive manner to help overcome any obstacles
you may face during installation. Please read our instructions carefully
and follow them carefully step-by-step.
Installing the Mainboard 2-3
(1)Standard External Connectors
Inside the case of any computer several cables and plugs have to be
connected. These cables and plugs are usually connected one-by-one to
connectors located on the mainboard. You need to carefully pay
attention to any connection orientation the cables may have and, if any,
notice the position of the first pin of the connector. In the explanations
that follow, we will describe the signifigance of the first pin.
PN1 - Keylock connector Please pay attention to pin position and
orientation
This connector has a specific orientation. Connect the five-thread
keylock connector cable to the PN1 connector pins on the mainboard.
Pin number Name or significance of signal
1 +5VDC
2 No connection
3 Ground
4 Keyboard inhibit Signal
5 Ground
2-4 Chapter 2
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The “keylock switch” is used to lock the computer’s
keyboard. This disables the keyboard so that
unauthorized persons cannot use it. When this function
is in use, you will need to use the unlock key to activate
the keyboard.
PN1 - IDE LED connector
This connector has a specific orientation. Connect the two-thread IDE
LED connector cable attached to the case to the IDE LED connector on
the mainboard.
Pin number Name or significance of signal
7 LED’s Cathode
8 LED’s Anode
PN1 - Standby connector
There is no specific orientation. Most of the present AT cases do not
support this feature so most of you can ignore this instruction. If your
case has a cable for the Standby feature, you should connect this cable to
the connector on the Mainboard.
Pin number Name or significance of signal
10 Standby power supply<+5VSB>
11 Control signal of computer switch of the case
The “standby connector,” unlike the traditional mechanical
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switch, is an electronic way to turn the computer’s power
off. To use this feature, the power supply system must
permit a shutdown power supply (+5VSB), support the
electronic switch feature, and must also be used with
connector JS1 on the mainboard. For example, when
using Windows 95, your computer will automatically shut
down after having saved your work when you exit
Windows. You do not need to use the mechanical
switch to turn the computer off.
PN1 - Hardware Suspend switch
Installing the Mainboard 2-5
There is no specific orientation. Connect the two-thread hardware
suspend plug to the PN1 connector pins on the mainboard. Since
most cases do not support this feature, most of you ignore this instruction.
Furthermore, this feature is not necessary as it is already a part of the
mainboard.
Pin number Name or significance of the signal
13 Suspend
14 Ground
PN2 - Hardware Reset connector
There is no specific orientation. Connect the two-thread hardware reset
cable to the PN2 connector pins on the mainboard.
Pin number Name or significance of signal
1 Ground
2 Hardware reset signal
The “Hardware Reset” is used to reset the computer
during operation without turning the computer off and
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back on. For example, if you are running an application
that stops responding to the computer, you may press the
Reset button to restart the computer.
PN2 - Speaker connector
There is no specific orientation. Connect the four-thread speaker cable to
the PN2 connector pins on the mainboard.
Pin number Name or significance of signal
4 +5VDC
5 Ground
6 Ground
7 Sound Signal
2-6 Chapter 2
PN2 - Turbo switch LED connector
This connector has a specific orientation. Connect the two-thread turbo
switch LED plug to the PN2 connector pins on the mainboard.
Pin number Name or significance of signal
9 Anode terminal of Turbo LED
10 Cathode terminal of Turbo LED
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The “hardware Turbo LED” indicates the status of
hardware operating speed.
JS1 - Power Control connector
This has a specific orientation. The present power supply units of AT
computer do not support this feature, so you can ignore this connector. If
your power supply unit features this connector, insert plug JS1, but be sure
that the signification of the signal cable is the same, and be sure to use this
feature in connection with the Standby connector on connector PN1.
Pin number Name of the signal or signification
1 Power supply control signal <PS_ON>
2 Standby power supply <+5VSB>
3 Ground
Installing the Mainboard 2-7
FAN - CPU Fan power connector
This has a specific orientation. Connect the three-threads CPU fan cable to
the Fan connector.
Pin number Name of the signal or signification
1 Ground
2 +12V
3 Ground
Mouse - PS/2 Mouse connector Watch the pin number and the
orientation
This has a specific orientation. Connect the six-threads PS/2 Mouse cable
provided to the Mouse connector on the mainboard.
Pin number Name of the signal or signification
1 Mouse data
2 No connection
3 Ground
4 +5VDC
5 Ground
6 Mouse clock
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The “PS/2 Mouse Port” is different from COM1 or COM2
serial ports to which you can also connect a Mouse. This
mainboard features an extra PS/2 Mouse port, so when you
buy a mouse, be sure that it is a PS/2 Mouse before
connecting it to this port. But if you cannot find any PS/2
Mouse, you can still use COM1 or COM2 to connect a
serial mouse to your computer.
2-8 Chapter 2
J2 - Keyboard Connector
This has an orientation pin. Connect your keyboard connector to connector
J2 on the mainboard.
Pin number Name of the signal or signification
1 Keyboard clock
2 Keyboard data
3 No connection
4 Ground
5 +5VDC
P8/P9 - Power input Connectors Watch the pin number and the
orientation
These have a specific orientation. The three warning marks indicate that if
you make a mistake in pin number or connection orientation, you could
destroy your equipment. During installation, you just need to connect to the
correct pins and in the correct orientation, and to connect connectors P8
and P9 of the power supply unit to the connectors on the mainboard.
Pin number
1 POWERGOOD 7 Ground
2 +5VDC 8 Ground
3 +12VDC 9 -5VDC
4 -12VDC 10 +5VDC
5 Ground 11 +5VDC
6 Ground 12 +5VDC
Name of the signal or
signification
Pin number
Name of the signal or
signification
Installing the Mainboard 2-9
IR - Infrared remote Connector Watch the pin number and the
orientation
This has a specific orientation. Your mainboard supports this feature, but
you must buy the infrared remote device as an option.
Pin number Name of the signal or signification
1 +5VDC
2 No connection
3 Receive data
4 Ground
5 Transmit data
I/O Port connectors Watch the pin number and the orientation
Connector name Pin number Name of the peripheral connected
IDE 1 40 IDE Channel 1
IDE 2 40 IDE Channel 2
FDC 34 Floppy Disk connector
LPT 26 Parallel port connector
COM1 10 Serial port COM1 connector
COM2 10 Serial port COM2 connector
USB 16 Universal Serial Bus connector
2-10 Chapter 2
(2)Jumpers and Switches
CCMOS : Delete the contents of the CMOS
This jumper is set on pins 1 and 2 at the factory, in order for
the computer to function normally, so please do not change
this setting. The main feature of this jumper is to solve
situations where the computer crashes due to improper usage.
For instance:
l You have forgotten the password you set.
l You have changed inappropriately the settings in the BIOS
menu.
l You want to change the version of flash BIOS.
All these errors are very serious, you must avoid them. But if
you have made one of these errors, this jumper can save your
life. First turn off the power supply and open the computer
case, than place the jumper on pins 2 and 3 in order to save
your computer. But if you use your computer normally, you
should not need to use this feature.
After you have deleted theCMOS information, the computer is saved, but
you still have to go back to the BIOS Setup menu, and reset one by one
all the specifications: CPU, date, hour, FDD and HDD parameters. etc.,
before your computer will get back into normal operation.
JC1: Installing the cache memory in the cache memory extension
slot (COAST)
On delivery, the IT5 mainboard comes with a 256K or 512K
cache memory. If you already have 512K, your mainboard will
not need a cache extension, and you will not be able to see the
extension slot. But if you have only 256K, we have reserved an
extension slot which permits you to extend the cache to 512K.
This is set up at the factory with no jumper, which is what we
call OFF status. You will need to put the jumper in place only
when you extend the cache. For more details, refer to the section
which deals with cache memory.
Installing the Mainboard 2-11
(3)Presentation and Installation of the CPU
Jumperless MainBoard (Mainboard with no DIP Switch or Jumper)
This mainboard series can be installed with CPU without the hardware
setting of the CPU.
On other boards, when you want to install the CPU, you have, more or
less, to setup some jumpers or DIP switches. With this mainboard, you will
not need to adjust any jumper or switch. The CPU speed and model is set
up by software, in order to allow the user to complete setup and installation
procedures easily. After you have inserted the CPU on the CPU socket, you
can close the computer case and turn the computer on. You just need to
enter the CPU SOFT MENU™ located in the BIOS Setup, and to setup the
speed and the voltage of the CPU to compete the installation. Even if you
don’t need to setup any switch, we recommend you to read our presentation
of the CPUs, it will be useful information for you.
Since 1996, every two or three months, Intel adds new models to the
Pentium CPU series. That is why the CPU market is filled with a lot of
different models and brands. All CPUs have different electrical
specifications. That’s why installing a CPU is becoming more and more
complex. You can’t help that, because everybody wants to be able to
upgrade its hardware. So, you have to take a bit of time to read this section,
in order to be able to install a cheaper and better processor.
This mainboard does not only support all the CPUs listed in the
specifications, but also has reserved several circuits in order to be able to
support future processors. But before we go further in our presentation, we
must clarify that “we have only tested the CPUs listed in Chapter 1”, we
cannot guarantee that this board will be able to support future products,
because we cannot forecast future developments. But we will do our best
to support any possible CPU.
Related terminology :
External clock
Also referred to as the external CPU clock, or “Bus clock”, it is the
input clock of the CPU. For instance, Intel Pentium P90, P120 and
P150 all have a 60MHz external CPU clock, but have different internal
clock multiplier factors.
Clock multiplier factor
2-12 Chapter 2
The real operation clock within the CPU is the multiple of the external
clock. We refer to this factor as the clock multiplier factor. The four
factors possible are 1.5, 2, 2.5 and 3. The factor differs from one CPU
to another. For instance, the Intel Pentium 166 CPU has a 66MHz
external clock, with a multiplier factor of 2.5, so that the speed of the
internal clock is 66MHz x 2.5.
Internal clock
Also referred to as the real internal CPU clock, it is the actual internal
operating clock of the CPU. The Internal Clock is a multiple of the
external clock and of the clock multiplier factor. For instance, the Intel
Pentium 90 CPU has a 60MHz external clock and its clock multiplier
factor is 1.5; the Intel Pentium P133 CPU has a 66MHz external clock
and its clock multiplier factor is 2.
Internal CPU clock = clock multiplier factor x external CPU clock
AT Bus clock
Also referred to as ISA SPEED, or AT CLOCK, or even ISA Bus
clock. Ten years ago, the original specification of AT Bus clock
installed in the first generation PC/AT computers was 8MHz, this
means that there are some interface cards which can only work at
8MHz. In order to guarantee compatibility with older hardware, we
still support 8MHz AT Bus clock, but if your interface card is newer
or faster, you can choose a higher speed for the AT Bus clock, in
order to increase the transmission rate of the interface cards. But we
recommend you not to be too ambitious. An 8MHz setup ensures
maximum compatibility.
CPU Voltage - Vcore and Vio
From the voltage point of view, 586 series CPU can be divided into
two categories: single voltage CPU and dual voltage CPUs. Single
voltage CPUs include: Intel Pentium P54C series, AMD-K5 and Cyrix
6x86, etc.
Dual voltage CPUs include: Intel P55C with MMX, future AMD
CPUs, Cyrix 6x86L and M2.
The voltage of dual voltage CPUs has two components: Vcore and
Vio. Vcore provides all the power for internal processing, and its
power consumption is quite important. Vio provides the power
necessary for the external interface of the CPU.
Installing the Mainboard 2-13
P-Rating
The P-Rating was defined by some manufacturers other than Intel to
rate the performance of their CPU in comparison with Intel Pentium
CPUs. For instance, Cyrix 6x86 P166+ has a higher actual speed
compared with Intel Pentium P166, its internal clock needs only
133MHz versus 166MHz for Intel’s product. The main reason is that
Cyrix has improved the internal architecture of the 6x86 CPU, which
means that with the same internal clock speed, the actual clock speed
will be different.
Having read the related terminology above, please refer to the information
in appendices B, C or D for the type and specifications of your own CPU.
We suggest that you note down these specifications, which will help you
when you install the CPU.
CPU Settings:
!! CPU SOFT MENU !!
To configure the speed and the voltage of the CPU, you must enter to the
CPU SOFT MENU in BIOS Setup.
2-14 Chapter 2
(4)Installing Pipeline Burst SRAM
This mainboard features a 256K or 512K cache memory. It also
features a cache memory extension socket (COAST) in order to permit you
to upgrade 256K cache to 512K, and this with only one JC1 to choose from.
Installation is very easy. Refer to the table below:
Configuration
Mode 1 NO NO NO 0K OFF
Mode 2 YES NO NO 256K OFF
Mode 3 YES NO 256K module 512K ON
Mode 4 NO NO 256K module 256K OFF
Mode 5 NO NO 512K module 512K ON
Mode 6 NO YES NO 512K OFF
With 32K32
SRAM
With 64K32
SRAM
Cache socket Cache total
JC1
settings
<Notes>1. If your mainboard features a 512K cache when it is delivered
from the factory (Mode 6 in the table), the mainboard will not
have any cache extension slot (COAST) or JC1 jumper.
2. The configurations listed in the table are all the possible
configurations reserved when the board was designed. The
actual configuration when the board is delivered depends
mainly on the demands of the market.
Installing the Mainboard 2-15
(5)Installing System Memory<DRAM Memory>
When this mainboard was designed, we not only have taken into
account the present needs, but we have also tried to care about demands for
future upgrades:
1. Two 168-pin DIMM sockets:
Within 3 to 5 years, you may not be able to buy 72-pin SIMM
memory modules anymore, just as now you cannot find 30-pin
SIMM memory modules anymore. If you want to extend your
memory capacity, you will have no solution other than to use 168pin 3.3V unbuffered DIMM sockets.
2. Four 72-pin SIMM sockets:
Currently, the most common memory modules on the market are
72-pin SIMM modules. The four 72-pin SIMM sockets of this
mainboard will meet your needs.
3. Easy installation
You just need to insert the modules, without the help of God. Isn’t
it great?
Besides the features mentioned above, you can use simultaneously 72-pin
SIMM modules and 168-pin DIMM modules, but you will rarely encounter
this kind of configuration. Before you proceed with installation, be patient,
first read what follows:
1. Factory default setting of the mainboard is for 70ns FP or
EDO modules.
If your memory modules are faster than 70ns, say 60ns or 45ns,
you can modify the BIOS settings in order to speed up the
operating speed of the system. But if you don’t want to modify
these settings, or if you don’t know how to modify them, it’s no
big deal.
But if you set the external CPU clock at 66MHz or more, we
recommend you use 60ns or even faster DRAM modules.
2. Memory error check and correction feature on this
mainboard.
2-16 Chapter 2
IT5V: No support. Since the Intel 430VX chipset does not
support this feature, since the memory error check and
correction feature may not be effective, and since you
cannot easily find memory modules with memory check
and correction feature, this mainboard does not support
it.
IT5H: Support. In a server or network environment, demands
regarding system stability and data security are higher,
that is why these systems have to rely on hardware
security supported by software, and that is also the
reason why this mainboard features automatic memory
error check and correction.
3. Maximum memory capacity supported by this mainboard.
IT5V: 128M Bytes. It is the upper limit supported by the 430 VX
chipset.
IT5H: 512M Bytes. It is the upper limit supported by the 430 HX
chipset.
Computer
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<Relationships between memory modules and Pentium
CPUs>
Pentium, 6x86 and AMD-K5 are all 64 bit CPUs, but 72-pin
SIMM modules are only 32-bit. That’s why they have to be
used in pairs, because the CPU will always be only able to
see 64 bits. This means that 72-pin SIMM modules have to
be installed in pairs. For instance, SIMM1 and SIMM2 must
form a pair, and SIMM3 and SIMM4 must form another
pair. Of course, the two members of a pair must be of the
same kind <EDO or FP DRAM>, and you cannot use pairs
from different “species”.
But this series supports different “pairs” and use different
type of memory modules, notice:
l<SIMM1 and SIMM2>must use the same memory
type, as well as<SIMM3 and SIMM4>.
Installing the Mainboard 2-17
l<SIMM1 and SIMM2>use the same memory type,
and <SIMM3 and SIMM4>can use the same
type, or a different type, in order to permit you to
obtain the best speed configuration for each
“single” pair, and to make the system work at its
maximum capacity. If one memory pair is slower, it
will have no influence on the pair whose speed is
higher.
168-pin DIMM modules are 64 bit, so you can use single
modules. On the IT5V mainboard, these modules can
support not only EDO and FR DRAM, but also
Synchronous DRAM memory configurations. The IT5H
mainboard does not support SDRAM.
When you install DIMM modules on the mainboard, you don’t have to
setup anything, just be sure that you use 3.3V unbuffered 168-pin DIMM
modules, and insert them in the memory socket.
Computer
knowledge
After installing the DRAM, the BIOS of the mainboard will automatically
detect the size of the memory installed on the mainboard. Below is a list of
all the possible situations:
Scenario 1: You use only 72-pin SIMM modules:
<168-pin DIMM modules specifications>
According to the standards defined by JEDEC, there are a
lot of different types of specifications for 168-pin DIMM
sockets. Here are the possible types:
l 3.3V UNBUFFERED DIMM
l 3.3V BUFFERED DIMM
l 5V UNBUFFERED DIMM
l 5V BUFFERED DIMM
These types of DIMM modules differ not only by the
electrical design, but also by their architecture. So, if you
buy different types of DIMM modules, you will not be able
to insert them in the DIMM sockets. Currently, the standard
for PC is 3.3V UNBUFFERED DIMM, which is the
standard supported by this series.
l The maximum memory size is 128M bytes.
2-18 Chapter 2
l Support possible for single density or double density
memory modules.
l Memory modules supported: 1Mx32<4M>, 2Mx32
<8M>, 4Mx32<16M>or 8Mx32<32M>.
l <SIMM1 and SIMM2>is the first pair, <SIMM3 and
SIMM4>is the second pair. Usually, you first insert the
first pair, than the second pair, but it is possible to do the
reverse.
l You can also directly refer to table 2-1.
Scenario 2: You use only 168-pin DIMM modules:
l The maximum memory size is: IT5V: 128M Bytes.
IT5H: 256M Bytes.
l Support possible for single density or double density
memory modules.
l Memory modules supported: 1Mx64<8M>, 2Mx64
<16M>or 4Mx64<32M>.
l DIMM1 is the first pair, DIMM2 is the second pair.
Usually, you first insert modules in DIMM1 socket, than in
DIMM2 socket, but it is possible to do the reverse.
l You can also directly refer to table 2-2.
Scenario 3: You use 72-pin SIMM modules and 168-pin DIMM modules:
l The maximum memory size is: IT5V: 128M Bytes.
IT5H: 512M Bytes.
l Support possible for single density or double density
memory modules.
l Memory modules supported: Refer to case 1 and case 2
above.
l Support possible for mixed use of single density and
double density modules.
l Since there is a lot of possible configurations, no table is
given.
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