ASUS P2BN User Manual

®

P2B-N

Pentium®III / Pentium® II / Celeron™

NLX Motherboard

USER’S MANUAL

USER'S NOTICE

No part of this manual, including the products and software described in it, may be repro­duced, transmitted, transcribed, stored in a retrieval system, or translated into any language in
any form or by any means, except documentation kept by the purchaser for backup purposes,
without the express written permission of ASUSTeK COMPUTER INC. (“ASUS”).

ASUS PROVIDES THIS MANUAL “AS IS” WITHOUT WARRANTY OF ANY KIND,
EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED T O THE IMPLIED
WARRANTIES OR CONDITIONS OF MERCHANT ABILITY OR FITNESS FOR A PAR­TICULAR PURPOSE. IN NO EVENT SHALL ASUS, ITS DIRECTORS, OFFICERS,
EMPLOYEES OR AGENTS BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDEN­TAL, OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF
PROFITS, LOSS OF BUSINESS, LOSS OF USE OR DATA, INTERRUPTION OF BUSI­NESS AND THE LIKE), EVEN IF ASUS HAS BEEN ADVISED OF THE POSSIBILITY
OF SUCH DAMAGES ARISING FROM ANY DEFECT OR ERROR IN THIS MANUAL
OR PRODUCT.

Product warranty or service will not be extended if: (1) the product is repaired, modified or
altered, unless such repair, modification of alteration is authorized in writing by ASUS; or (2)
the serial number of the product is defaced or missing.

Products and corporate names appearing in this manual may or may not be registered trade­marks or copyrights of their respective companies, and are used only for identification or
explanation and to the owners’ benefit, without intent to infringe.

• Intel, LANDesk, and Pentium are registered trademarks of Intel Corporation.

• Celeron is a trademark of Intel Corporation.

• Vortex and Wavetracing are trademarks of Aureal Semiconductor Incorporated.

• IBM and OS/2 are registered trademarks of International Business Machines.

• Symbios is a registered trademark of Symbios Logic Corporation.

• Windows and MS-DOS are registered trademarks of Microsoft Corporation.

• Adobe and Acrobat are registered trademarks of Adobe Systems Incorporated.
The product name and revision number are both printed on the product itself. Manual revi-

sions are released for each product design represented by the digit before and after the period
of the manual revision number. Manual updates are represented by the third digit in the manual
revision number.

For previous or updated manuals, BIOS, drivers, or product release information, contact ASUS
at http://www.asus.com.tw or through any of the means indicated on the following page.

SPECIFICATIONS AND INFORMATION CONTAINED IN THIS MANUAL ARE FUR­NISHED FOR INFORMATIONAL USE ONLY, AND ARE SUBJECT TO CHANGE AT
ANY TIME WITHOUT NOTICE, AND SHOULD NOT BE CONSTRUED AS A COM­MITMENT BY ASUS. ASUS ASSUMES NO RESPONSIBILITY OR LIABILITY FOR
ANY ERRORS OR INACCURACIES THAT MA Y APPEAR IN THIS MANUAL, INCLUD­ING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.

Copyright © 1999 ASUSTeK COMPUTER INC. All Rights Reserved.

Product Name: ASUS P2B-N
Manual Revision: 1.04 E407
Release Date: July 1999

2 ASUS P2B-N User’s Manual

ASUS CONTACT INFORMATION

ASUSTeK COMPUTER INC. (Asia-Pacific)

Marketing

Address: 150 Li-Te Road, Peitou, Taipei, Taiwan 112
Telephone: [phone]
Fax: [phone]
Email: [e-mail]

Technical Support

Tel (English): [phone] ext. 706
Tel (Chinese): [phone] ext. 111
Fax: [phone]
Email: [e-mail]
Newsgroup: news2.asus.com.tw
WWW: www.asus.com.tw
FTP: ftp.asus.com.tw/pub/ASUS

ASUS COMPUTER INTERNATIONAL (America)

Marketing

Address: 6737 Mowry Avenue, Mowry Business Center, Building 2

Newark, CA 94560, USA
Fax: [phone]
Email: [e-mail]

Technical Support

Fax: [phone]
BBS: [phone]
Email: [e-mail]
WWW: www.asus.com
FTP: ftp.asus.com.tw/pub/ASUS

ASUS COMPUTER GmbH (Europe)

Marketing

Address: Harkort Str. 25, 40880 Ratingen, BRD, Germany
Telephone: [phone]
Fax: [phone]
Email: [e-mail]

Technical Support

Hotline: [phone]
BBS: 49-2102-448690
Email: [e-mail]
WWW: www.asuscom.de
FTP: ftp.asuscom.de/pub/ASUSCOM

ASUS P2B-N User’s Manual 3

CONTENTS

1. INTRODUCTION .............................................................................. 7

1.1 How This Manual Is Organized .................................................. 7

1.2 Item Checklist ............................................................................. 7

1.2.1 Motherboard....................................................................... 7

1.2.2 Riser Card .......................................................................... 7

2. FEATURES ......................................................................................... 8

2.1 The ASUS P2B-N Motherboard ................................................. 8

2.1.1 Specifications..................................................................... 8

2.1.2 Special Features ................................................................. 9

2.1.3 Performance Features ...................................................... 10

2.1.4 Intelligence....................................................................... 10

2.2 ASUS P2B-N Parts ................................................................... 11

3. HARDWARE SETUP ...................................................................... 12

3.1 Motherboard Layout ................................................................. 12

3.2 Riser Cards................................................................................ 14

3.2.1 NLX-R Riser Card ........................................................... 14

3.2.2 B9-N Riser Card .............................................................. 14

3.2.3 Yeong-Yang Riser Card ................................................... 14

3.3 Hardware Setup Procedure ....................................................... 17

3.4 Motherboard Settings................................................................ 17

3.5 System Memory (DIMM) ......................................................... 23

3.5.1 General DIMM Notes ...................................................... 23

3.5.2 DIMM Memory Installation ............................................ 24

3.6 Central Processing Unit (CPU) ................................................. 25

3.6.1 Universal Retention Mechanism...................................... 25

3.6.2 Heatsinks.......................................................................... 25

3.6.3 Installing the Processor .................................................... 26

3.6.4 ASUS Smart Thermal Solutions ...................................... 28

3.6.5 Recommended Heatsinks for Slot 1 Processors .............. 29

3.7 Expansion Cards ....................................................................... 30

3.7.1 Expansion Card Installation Procedure............................ 30

3.7.2 Assigning IRQs for Expansion Cards .............................. 30

3.7.3 Assigning DMA Channels for ISA Cards ........................ 31

3.7.4 ISA Cards and Hardware Monitor ................................... 31

3.8 External Connectors.................................................................. 32

3.8.1 Back Panel Connectors .................................................... 32

3.8.2 Midboard Connectors ...................................................... 35

3.8.3 Riser Card Connectors ..................................................... 36

3.9 Power Connection Procedures .................................................. 41

4 ASUS P2B-N User’s Manual

CONTENTS

4. BIOS SETUP.................................................................................... 42

4.1 Managing and Updating Your BIOS ......................................... 42

4.1.1 Upon First Use of the Computer System ......................... 42

4.1.2 Updating BIOS Procedures (only when necessary)......... 43

4.2 BIOS Setup ............................................................................... 45

4.3 Standard CMOS Setup .............................................................. 46

4.4 BIOS Features Setup................................................................. 49

4.5 Chipset Features Setup.............................................................. 52

4.6 Power Management Setup ........................................................ 55

4.7 PNP and PCI Setup ................................................................... 58

4.8 Load BIOS Defaults.................................................................. 60

4.9 Load Setup Defaults.................................................................. 60

4.10 Supervisor and User Password ................................................. 61

4.11 IDE HDD Auto Detection ......................................................... 62

4.12 Save & Exit Setup..................................................................... 63

4.13 Exit W ithout Saving.................................................................. 63

5. SOFTWARE SETUP ....................................................................... 65

5.1 Support CD Main Menu (Windows 98).................................... 65

5.3 LDCM Local Setup................................................................... 68

5.4 LDCM Administrator Setup...................................................... 70

5.5 ASUS PC Probe ........................................................................ 71

5.6 ASUS LiveUpdate .................................................................... 72

5.6 Driver ........................................................................................ 73

5.7 Other ......................................................................................... 76

5.8 Uninstalling Programs .............................................................. 78

5.9 DOS and Windows 3.1 Setup for Novell .................................. 79

5.10 Windows NT Server or Workstation ......................................... 80

5.11 Windows 95 .............................................................................. 82

5.12 Select Duplex Mode (optional)................................................. 83

6. SOFTWARE REFERENCE ........................................................... 85

6.1 ASUS PC Probe ........................................................................ 85

6.2 AudioRack32 ............................................................................ 91

6.3 Display Settings for Windows 95/98 ...................................... 100

6.4 Desktop Management Interface (DMI)................................... 102

7. APPENDIX...................................................................................... 105

7.1 PCI-L101 Fast Ethernet Card ................................................. 105

7.2 S370 Series CPU Cards .......................................................... 107

7.3 Network Controller ................................................................. 109

7.4 Glossary .................................................................................. 115

ASUS P2B-N User’s Manual 5

FCC & DOC COMPLIANCE

Federal Communications Commission Statement

This device complies with FCC Rules Part 15. Operation is subject to the following
two conditions:

• This device may not cause harmful interference, and

• This device must accept any interference received, including interference that
may cause undesired operation.

This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference in a residential installa­tion. This equipment generates, uses and can radiate radio frequency energy and, if
not installed and used in accordance with manufacturer's instructions, may cause
harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by
turning the equipment off and on, the user is encouraged to try to correct the inter­ference by one or more of the following measures:

• Re-orient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment to an outlet on a circuit different from that to which
the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

WARNING! Any changes or modifications to this product not expressly ap-

proved by the manufacturer could void any assurances of safety or performance
and could result in violation of Part 15 of the FCC Rules.

Canadian Department of Communications Statement

This digital apparatus does not exceed the Class B limits for radio noise emissions
from digital apparatus set out in the Radio Interference Regulations of the Cana­dian Department of Communications.

This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.

6 ASUS P2B-N User’s Manual

1. INTRODUCTION

1.1 How This Manual Is Organized

This manual is divided into the following sections:

1. Introduction Manual information and checklist

2. Features Information and specifications concerning this product

3. Hardware Setup Instructions on setting up the motherboard and jumpers

4. BIOS Setup Instructions on setting up the BIOS software

5. Software Setup Instructions on setting up the included support software

6. Software Reference Reference material for the included support software

7. Appendix Optional items and general reference

1.2 Item Checklist

Please check that your package is complete. If you discover damaged or missing
items, please contact your retailer.

1.2.1 Motherboard

Manual / Checklist

1. INTRODUCTION

(1) ASUS motherboard
(1) Universal retention mechanism for SECC2/SECC/SEPP
(1) Support CD with drivers and utilities
(1) Motherboard User’s Manual

(1) System housing User’s Manual
(1) NLX Form-factor system housing, riser card, and power supply

ASUS Slim CD-ROM (optional)
S-P2FAN or P2T-Cable for Slot 1 processors (optional)
IrDA-compliant infrared module (optional)
ASUS S370 CPU card series (optional)
ASUS PCI-L101 Wake-On-LAN 10/100 Ethernet Card (optional)

NOTE: This motherboard only works with ASUS riser cards. See your dealer for
more information.

1.2.2 Riser Card

(1) ASUS Riser Card
(1) UltraDMA/33 IDE + 3.5” floppy disk drive connector set

OR

(1) UltraDMA/66 IDE cable and (1) 3.5” floppy disk drive cable
(1) Bag of spare jumper caps
(1) FDC slim CD-ROM cable (optional)

ASUS P2B-N User’s Manual 7

2.1 The ASUS P2B-N Motherboard

The ASUS P2B-N is carefully designed for the demanding PC user who wants ad­vanced features processed by the fastest CPU.

2.1.1 Specifications

• NLX: Features ASUS’ custom designed NLX form factor.

• Multi-Speed: Supports Intel Pentium

2. FEATURES

Specifications

• Multi-Cache: Supports processors with 512, 256, 128, or 0KB Pipelined Burst

• Anti-Boot Virus BIOS: Features a programmable BIOS, offering enhanced

• Intel AGPset: Features Intel’s 440BX AGPset with I/O subsystems and front-side bus

2. FEATURES

®

III (450MHz and faster), Pentium® II

(233MHz to 450MHz), and Celeron

Level 2 cache.

Advanced Configuration Power Interface (ACPI) support for Windows 98 com-
patibility , built-in firmware-based virus protection through T rend ChipA way V irus
codes, and autodetection of most devices for virtually automatic setup.

(FSB) platform, which boosts the traditional 66MHz external bus speed to 100MHz.

TM

SEPP (266MHz and faster) processors.

• PC100 Memory Support: Equipped with two DIMM sockets to support Intel

PC100-compliant SDRAMs (8, 16, 32, 64, 128, or 256MB) up to 512MB. These
new SDRAMs are necessary to meet the critical enhanced 100MHz bus speed
requirement.

• 100/10Mbps LAN (optional): Features an onboard Intel 82558 Ethernet LAN

Controller (fully integrated 10BASE-T/100BASE-TX) and a LAN Activity LED
for monitoring network conditions.

• AGP VGA (optional): Features an onboard ATI 3D Rage Pro AGP 2X (8MB

SDRAM) or Rage IIC (4MB SDRAM) for 3D hardware acceleration.

• PCI Audio (optional): Features onboard the ESS Solo-1 32-bit 3D positional

PCI audio which supports games and applications for Sound Blaster
Blaster Pro and full-duplex stereo.

• Thermal Sensor Connector with Optional Sensor: Accurately detects the CPU

temperature of processors with the ASUS Smart Fan or the Intel boxed proces­sor heatsink with fan when connected to an ASUS P2T-Cable.

• Hardware Monitoring (optional): Provides an easier way to examine and man-

age system status information, such as CPU and system voltages, temperatures,
and fan status through the onboard hardware ASIC and the bundled LDCM by
Intel or PC Probe from ASUS.

TM

and Sound

• Riser Cards: Provides NLX power, IDE, floppy drive, LAN wake up connec-

tors; PCI/ISA slots; and USB and IrDA support.

• Ultra DMA/33 BM IDE: Comes with an onboard PCI Bus Master IDE controller

with two connectors that supports four IDE devices in two channels, supports Ultra
DMA/33, PIO Modes 3 and 4 and Bus Master IDE DMA Mode 2, and supports
Enhanced IDE devices, such as Tape Backup, CD-ROM, and LS-120 drives.

8 ASUS P2B-N User’s Manual

2. FEATURES

• Universal Retention Mechanism: Supports a Pentium® III / II processor pack-

aged in a Single Edge Contact Cartridge (SECC2/SECC) or a Celeron
sor packaged in a Single Edge Processor Package (SEPP).

• Wake-On-LAN Connector: Supports Wake-On-LAN activity through an op-
tional ASUS PCI-L101 10/100 Fast Ethernet PCI card (see 7.1 PCI-L101 LAN
Card) or a similar ethernet card.

• IrDA: Includes/supports an infrared module for wireless interface.

• Slim CD-ROM: Supports an optional ASUS slim CD-ROM drive for ASUS’
custom designed NLX form factor.

2.1.2 Special Features

• ACPI Ready: Advanced Configuration Power Interface (ACPI) provides more
Energy Saving Features for operating systems that support OS Direct Power
Management (OSPM) functionality . W ith these features implemented in the OS,
PCs can be ready around the clock, yet satisfy all the energy saving standards.
To fully utilize the benefits of ACPI, an ACPI-supported OS, such as Windows
98, must be used.

TM

proces-

Specifications

2. FEATURES

• Suspend and Go: Suspend-to-RAM provides maximum power savings as an

TM

alternative to leaving the computer ON and QuickStart
asleep waiting for system bootup (Suspend-to-RAM supported OS required).

• Desktop Management Interface (DMI): Supports DMI through BIOS, which
allows hardware to communicate within a standard protocol creating a higher
level of compatibility. (Requires DMI-enabled components.)

• Easy Installation: Incorporates BIOS that supports autodetection of hard disk
drives, PS/2 mouse, and Plug and Play devices to make the setup of hard disk
drives, expansion cards, and other devices virtually automatic.

• PC’98 Compliant: Both the BIOS and hardware levels of ASUS smart series
motherboards meet PC’98 compliancy. The new PC’98 requirements for sys­tems and components are based on the following high-level goals: Support for
Plug and Play compatibility and power management for configuring and man­aging all system components, and 32-bit device drivers and installation proce­dures for Windows 95/98/NT.

• Symbios SCSI BIOS: Supports optional ASUS SCSI controller cards through
the onboard SYMBIOS firmware.

so that you do not fall

2.1.3 Performance Features

• Concurrent PCI: Concurrent PCI allows multiple PCI transfers from PCI mas-

ASUS P2B-N User’s Manual 9

2. FEATURES

ter busses to the memory and processor.

• Double the IDE Transfer Speed: ASUS smart series motherboards with Intel

chipsets improves IDE transfer rate using Bus Master UltraDMA/33 IDE which
can handle data transfer up to 33MB/s.

• SDRAM Optimized Performance: Supports the new generation memory - Syn-

chronous Dynamic Random Access Memory (SDRAM) which increases the data
transfer rate to 800MB/s max using PC100-compliant SDRAM.

2. FEATURES

Specifications

2.1.4 Intelligence

• Dual Function Power Button: Pushing the power button for less than 4 sec-

• Fan Status Monitoring and Alarm (only w/ hardware monitor): To prevent

• Message LED (requires ACPI OS support): Turbo LEDs now act as informa-

• Remote Ring On (requires external modem): This allows a computer with this

onds when the system is in the working state places the system into one of two
states: sleep mode or soft-off mode, depending on the BIOS or OS setting (see
PWR Button < 4 Secs in 4.6 Power Management Setup). When the power
button is pressed for more than 4 seconds, the system enters the soft-off mode
regardless of the BIOS setting.

system overheat and system damage, the CPU, power supply, and system fans
can be monitored for RPM and failure. All fans are set for its normal RPM
range and alarm thresholds.

tion providers. Through the way a particular LED illuminates, the user can de­termine the stage the computer is in. A simple glimpse provides useful informa­tion to the user.

motherboard to be turned on remotely through an external modem. W ith this fea­ture, users can access their computers from anywhere in the world!

• System Resources Alert (only w/ hardwar e monitor): Today’ s operating sys-

tems such as Windows 95/98/NT and OS/2, require much more memory and
hard drive space to present enormous user interfaces and run large applications.
The system resource monitor will warn the user before the system resources are
used up to prevent possible application crashes. Suggestions will give the user
information on managing their limited resources more efficiently.

• T emperatur e Monitoring and Alert (only w/ hardware monitor): T o prevent

system overheat and system damage, there are heat sensors to monitor the CPU
(the Pentium III/II processors require a special heatsink with a thermal sensor)
and system temperatures to warn of damaging temperatures.

• Voltage Monitoring and Alert (only w/ hardware monitor): System voltage

levels are monitored to ensure stable voltage to critical motherboard compo­nents. Voltage specifications are more critical for future processors, so monitor­ing is necessary to ensure proper system configuration and management.

10 ASUS P2B-N User’s Manual

2. FEATURES

2.2 ASUS P2B-N Parts

T: PS/2 Mouse
B: PS/2 Keyboard

Intel 82558 LAN
Controller*

4MB (Rage IIC)/
8MB (Rage Pro)
VGA Memory*

Onboard ESS Audio*
2 DIMM Sockets

ATI 3D Rage Pro
AGP 2X/Rage IIC
VGA Chipset*

CPU Slot 1
Universal Folding

Retention Mechanism

COM 1

T: Parallel Conn.
B: Serial Conn.

COM 2

VGA Connector

Joystick/MIDI

Connector*LAN LED*RJ-45*

2. FEATURES

Motherboard Parts

Intel PIIX4E PCIset

Intel 440BX AGPset

Slim CD-ROM Connector

ASUS ASIC

Keyboard BIOS,
Multi-I/O

Programmable
Flash EEPROM

H/W Monitoring ASIC*

*Optional at the time of purchase

ASUS P2B-N User’s Manual 11

3. HARDWARE SETUP

3.1 Motherboard Layout

COM 1 COM 2

1

CPU_FAN

AMC

Motherboard Layout

3. H/W SETUP

Parallel

Port

Connector

CPU THEM

SDRAM

Rage Pro VGA: 8MB SDRAM
Rage IIC VGA: 4MB SDRAM

SDRAM

ATI 3D Rage

Pro AGP 2X/

SDRAM

SDRAM

Rage IIC

VGA

Chipset

PS/2

TOP:
MOUSE

BOTTOM:
KEYBOARD

CPU Slot 1

RJ-45

LAN_LED

VIO

VGA

JACK_CON

Intel 82558

Ethernet

LAN

Controller

LANDIS_EN

Intel

PIIX4E

Chipset

Joystick/MIDI

GAME

1

MODEM

PCI

Audio

AUDIS_EN

®

Intel

DIMM Socket 1 (64/72-bit, 168-pin module)

DIMM Socket 2 (64/72-bit, 168-pin module)

440BX

P2B-N

AGPset

Keyboard

BIOS, RTC,

& Multi-I/O

KB_WAKE

Flash EEPROM

(Programmable BIOS)

FS0
FS1
FS2

Row

CMOS
Power

CR2032

3 Volt Cell

CLR_RTC

CHASIS_FAN

32 10

BUS FREQ SELECT

(Grayed items are optional at the time of purchase.)

ASUS

ASIC

BF0

FREQ MULT

Hardware

Monitor

CDROM Connector

BF1

BF2

BF3

12 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

Motherboard Settings

1) VIO p. 18 Voltage Input/Output Selection

2) LANDIS_EN p. 18 LAN Setting (Enable/Disable)

3) AUDIS_EN p. 19 Audio Setting (Enable/Disable)

4) KB_WAKE p. 19 Keyboard Wake Up (Enable/Disable)

5) FS0, FS1, FS2 p. 20 CPU External Clock (Bus) Frequency Selection

6) BF0, BF1, BF2, BF3 p. 20 CPU Core:Bus Frequency Multiple

Sockets

1) DIMM1, DIMM2 p. 24 168-pin DIMM Memory Expansion Socket

2) CPU Slot 1 p. 25 CPU Support

Hardware Monitor

1) CPU THEM p. 29 Thermal Sensor Connector

Back Panel Connectors

1) PRINTER p. 32 Parallel Port Connector (25-pin female)

2) COM1, COM2 p. 32 Serial Port Connectors (Two 9-pin male)

3) PS2KBMS p. 33 PS/2 Mouse Connector (6-pin female)

4) PS2KBMS p. 33 PS/2 Keyboard Connector (6-pin female)

5) RJ-45 p. 33 Fast-Ethernet Port Connector

6) LAN_LED p. 33 LAN Diagnostic LEDs

7) VGA p. 34 Monitor (VGA) Output Connector (15-pin female)

8) GAME p. 34 Joystick or MIDI Connector (15-pin female)

Midboard Connectors

1) CPU_, CHASIS_FAN p. 34 CPU Fan Power (Two 3-pin blocks)

2) CDROM p. 35 CD-ROM Drive Connector (50-3 pins)

3) MODEM p. 35 Voice Modem In Connector (4 pins)

4) AMC p. 36 ATI Multimedia Connector (40-3 pin block)

5) JACK_CON p. 36 Back Panel Audio Connectors (10-1 pin block)

3. H/W SETUP

Layout Contents

ASUS P2B-N User’s Manual 13

3. HARDWARE SETUP

Y

3.2 Riser Cards

3.2.1 NLX-R Riser Card

CHASS_DET

NLX_EXT

NLX-R Riser Card Front

Riser Card Layouts

3. H/W SETUP

3.2.2 B9-N Riser Card

CHASS_DET

NLX_EXT

PCI2

PCI1

PCI3

®

PCI2

PCI1

®

ISA

ISA

B9-N

NLX-R

WAKEUP

LAN LED

WOL_CON

HEAD_SPK

NLX_SLOT

IR

CIR

NLX-R Riser Card Back

IDEA

IDEB

FLOPPY

NLX_SLOT

NOTE: Grayed items are optional

at the time of purchase.

FLOPPY

MIC-CON

FCON

IDE1

POWER

IR

USB

LED_CTRL

HEAD_SPK

JP-2K

USB1

B9-N Riser Card Front

ATXPWR

B9-N Riser Card Back

3.2.3 Yeong-Yang Riser Card

PCI1

SWITCH

YEONG-YANG

CDIN

NLX_EXT

eong-Yang Riser Card Front

SLOT1

PCI2

SLOT1A

WOL_CON

IDE2
IDE1

FLOPPY

RISER

MIC
USB
IR

Panel

PWRLED

HDD_LED

RESET

PWRSW

SPKR

Power

Yeong-Yang Riser Card Back

14 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

Riser Card Expansion Slots

1) ISA (NLX-R) p. 30 16-bit ISA Bus Expansion Slots*
ISA (B9-N) 16-bit ISA Bus Expansion Slots

SLOT1/1A (Yeong-Yang) 16-bit ISA Bus Expansion Slots

2) PCI1, PCI2 (NLX-R) p. 30 32-bit PCI Bus Expansion Slots
PCI1, PCI2, PCI3 (B9-N) 32-bit PCI Bus Expansion Slots

PCI1, PCI2 (Yeong-Yang) 32-bit PCI Bus Expansion Slots

Riser Card Connectors

1) CDIN (Yeong-Yang) p. 36 Stereo Audio In Connector

2) LAN_LED (NLX-R) p. 37 LAN Activity LED Connector (2 pins)
WOL_CON (NLX-R) Wake-On-LAN Connector (3 pins)
WAKEUP (B9-N) Wake-On-LAN Connector (3 pins)
WOL_CON (Yeong-Yang) Wake-On-LAN Connector (3 pins)

3) FCON (NLX-R) p. 37 Front Panel Connector (16-1 pins)
HEAD_SPK (NLX-R) Speaker Connector (4-1 pins)
LED_CTRL (B9-N) Front Panel Connector (16-1 pins)
HEAD_SPK (B9-N) Speaker Connector (4-1 pins)
PANEL (Yeong-Yang) Front Panel Connector (16-1 pins)

4) MIC-CON (NLR-R) p. 38 Front Panel Microphone Jack Connector (2 pins)
JP-2K (B9-N) Front Panel Microphone Jack Connector (2 pins)
MIC (Yeong-Yang) Front Panel Microphone Jack Connector (2 pins)

5) POWER p. 38 NLX Power Supply Connector (20-pin block)
ATXPWR NLX Power Supply Connector (20-pin block)
Power NLX Power Supply Connector (20-pin block)

6) IDE1 (NLX-R) p. 39 IDE Connector (40-1 pins)
IDEA, IDEB (B9-N) IDE Connectors (40-1 pins)
IDE1, IDE2 (Yeong-Yang) IDE Connectors (40-1 pins)

7) FLOPPY (NLX-R) p. 39 Floppy Drive Connector (34-1 pins)
FLOPPY (B9-N) Floppy Drive Connector (34-1 pins)
FLOPPY (Yeong-Yang) Floppy Drive Connector (34-1 pins)

8) USB (NLX-R) p. 40 USB Ports (Two 4-pin sockets)
USB1 (B9-N) USB Ports (Two 4-pin sockets)
USB (Yeong-Yang) USB Module Connector (5-1 pins)

9) IR, CIR (NLX-R) p. 40 IrDA-Compliant Infrared Module (Lenses)
IR (B9-N) Infrared Module Connector (10-1 pins)
IR (Yeong-Yang) Infrared Module Connector (5-1 pins)

3. H/W SETUP

Riser Card Contents

* The optional onboard hardware monitor uses the address 290H-297H, so legacy

ISA cards must not use this address or else conflicts will occur.

ASUS P2B-N User’s Manual 15

(This page was intentionally left blank.)

3. H/W SETUP

3. HARDWARE SETUP

16 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

3.3 Hardware Setup Procedure

Before using your computer, you must complete the following steps:

1. Check Motherboard Settings

2. Install Memory Modules

3. Install the Central Processing Unit (CPU)

4. Install Expansion Cards

5. Connect Ribbon Cables, Panel Wires, and Power Supply

6. Setup the BIOS Software

3.4 Motherboard Settings

This section explains in detail how to change your motherboard’s function settings
through the use of switches and/or jumpers.

W ARNING! Computer motherboards and expansion cards contain very delicate

Integrated Circuit (IC) chips. T o protect them against damage from static electric­ity, you should follow some precautions whenever you work on your computer.

1. Unplug your computer when working on the inside.

2. Use a grounded wrist strap before handling computer components. If you do

not have one, touch both of your hands to a safely grounded object or to a
metal object, such as the power supply case.

3. Hold components by the edges and try not to touch the IC chips, leads o r

connectors, or other components.

4. Place components on a grounded antistatic pad or on the bag that came with

the component whenever the components are separated from the system.

3. H/W SETUP

Motherboard Settings

ASUS P2B-N User’s Manual 17

3. HARDWARE SETUP

1) +3V Voltage Selection (VIO)

This jumper allows you to select the voltage supplied to the DRAM, chipset,
AGP, and the CPU’s I/O buffer . IMPORTANT! Setting this jumper to High V olt
(3.5V) may cause your system to become unstable. It is strongly recommended
that you leave this jumper on its default setting of Normal Volt (3.3V).

VIO Setting

Normal Volt [2-3] (default)
High Volt [1-2]

Motherboard Settings

3. H/W SETUP

P2B-N Voltage Input/Output Selection

2) LAN Setting (LANDIS_EN)

The onboard Intel 10/100 Fast Ethernet may be enabled or disabled using this
jumper. The default is set to Enable.

R

VIO

Normal
Voltage

(default)

3
2
1

VIO

High

Voltage

3
2
1

LANDIS EN Setting

Enable [2-3] (default)
Disable [1-2]

R

LANDIS_EN

3
2
1

Disable

(Default)

LANDIS_EN

3
2
1

Enable

P2B-N Onboard LAN Setting

18 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

3) Audio Setting (AUDIS_EN)

The onboard 32-bit PCI audio may be enabled or disabled using this jumper.

AUDIS EN Setting

Enable [2-3] (default)
Disable [1-2]

R

AUDIS_EN

321

Disable

AUDIS_EN

321

Enable

(Default)

P2B-N Onboard Audio Setting

4) Keyboard Wake Up (KB_WAKE)

This allows you to disable or enable the keyboard power up function. Set this
jumper to Enable if you wish to use your keyboard (by pressing the spacebar) to
power up your computer. This feature requires an ATX power supply that can
supply at least 300mAmp on the +5VSB lead. The default is set to Disable
because not all computers have the appropriate ATX power supply. Your com­puter will not power on if you set this to Enable and if you do not have the right
ATX power supply. WARNING! This jumper setting must coincide with the
BIOS setting (see “Power Up By Keyboard” in the Power Management Setup of
the BIOS SOFTWARE) or else conflicts will occur.

3. H/W SETUP

Motherboard Settings

R

P2B-N Keyboard Wake Up

ASUS P2B-N User’s Manual 19

KB WAKE Setting

Disable [1-2] (default)
Enable [2-3]

KB_WAKE

321

Disable

(Default)

KB_WAKE

321

Enable

3. HARDWARE SETUP

5) CPU Bus Frequency Selector (FS0, FS1, FS2)

This option tells the clock generator what frequency to send to the CPU, DRAM, and
AGPset. This allows the selection of the CPU’s External frequency (or BUS Clock).
The Bus Clock multiplied by the Bu s Multiple equals the CPU’s Internal frequency
(the advertised CPU speed).

Motherboard Settings

3. H/W SETUP

P2B-N CPU Bus Frequency Setting

6) CPU Core:Bus Frequency Multiple (BF0, BF1, BF2, BF3)

This option sets the frequency multiple between the Internal frequency of the
CPU and the CPU’ s External frequency . These must be set in conjunction with the

CPU Bus Frequency.

21

→
→
→

66.8MHZ

→
→

33.1MHZ

→
→
→

→

103.0MHZ

→

33.4MHZ

3

3

21

FS0
FS1
FS2

CPU
PCI

R

FS0
FS1
FS2

CPU
PCI

21

3

75.0MHZ

37.5MHZ
21

3

112.0MHZ

37.3MHZ

21

3

83.3MHZ

41.7MHZ
21

3

133.0MHZ

33.3MHZ

21

3

100.2MHZ

33.3MHZ

BF1

BF2

BF0

BF3

BF2

BF2

BF3

BF3

BF0

3.5x(7/2)3.0x(3/1)

BF0

6.0x(6/1)

BF1

BF2

BF0

BF3

BF1

BF2

BF0

BF1

BF1

BF2

BF2

BF3

BF0

BF3

5.5x(11/2)

BF3

BF0

BF1

BF1

8.0x(8/1)

3
2
1

2.0x(2/1)

BF1

BF0

3

®

2
1

3
2
1

4.5x(9/2)

BF1

BF0

7.0x(7/1)

BF2

BF2

2.5x(5/2)

BF3

BF0

5.0x(5/1)

BF3

BF0

7.5x(15/2)

P2B-N CPU Core:Bus Frequency Multiple Selection

BF1

BF1

BF2

BF2

BF0

BF3

4.0x(4/1)

BF3

BF0

6.5x(13/2)

BF1

BF1

BF2

BF2

BF3

BF3

20 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

Set the jumpers by the Internal speed of your processor as follows:

(CPU Bus Freq.) (Freq. Multiple)

Intel CPU Model Freq. Mult. Bus Fr eq. FS0 FS1 FS2 BF0 BF1 BF2 BF3

Pentium III 600MHz 6.0x 100MHz [1-2] [1-2] [1-2] [2-3] [2-3] [2-3] [1-2]
Pentium III 550MHz 5.5x 100MHz [1-2] [1-2] [1-2] [1-2] [1-2] [1-2] [2-3]
Pentium III 500MHz 5.0x 100MHz [1-2] [1-2] [1-2] [2-3] [1-2] [1-2] [2-3]
Pentium III/II 450MHz 4.5x 100MHz [1-2] [1-2] [1-2] [1-2] [2-3] [1-2] [2-3]
Pentium II 400MHz 4.0x 100MHz [1-2] [1-2] [1-2] [2-3] [2-3] [1-2] [2-3]
Pentium II 350MHz 3.5x 100MHz [1-2] [1-2] [1-2] [1-2] [1-2] [2-3] [2-3]

Celeron 500MHz 7.5x 66MHz [1-2] [1-2] [2-3] [1-2] [1-2] [2-3] [1-2]
Celeron 466MHz 7.0x 66MHz [1-2] [1-2] [2-3] [2-3] [1-2] [2-3] [1-2]
Celeron 433MHz 6.5x 66MHz [1-2] [1-2] [2-3] [1-2] [2-3] [2-3] [1-2]
Celeron 400MHz 6.0x 66MHz [1-2] [1-2] [2-3] [2-3] [2-3] [2-3] [1-2]
Celeron 366MHz 5.5x 66MHz [1-2] [1-2] [2-3] [1-2] [1-2] [1-2] [2-3]
Pentium II/Celeron 333MHz 5.0x 66MHz [1-2] [1-2] [2-3] [2-3] [1-2] [1-2] [2-3]
Pentium II/Celeron 300MHz 4.5x 66MHz [1-2] [1-2] [2-3] [1-2] [2-3] [1-2] [2-3]
Pentium II/Celeron 266MHz 4.0x 66MHz [1-2] [1-2] [2-3] [2-3] [2-3] [1-2] [2-3]
Pentium II 233MHz 3.5x 66MHz [1-2] [1-2] [2-3] [2-3] [2-3] [1-2] [2-3]

For updated processor settings, please visit ASUS’ web site (see ASUS CONTACT INFORMATION).

WARNING! Frequencies above 100MHz exceed the specifications for the

onboard Intel Chipset and are not guaranteed to be stable.

WARNING! PCI frequencies above 33MHz exceed the specifications for PCI

cards and are not guaranteed to be stable.

NOTE: Overclocking your processor is not recommended. It may result in a slower
speed. Voltage Regulator Output Selection (VID) is not needed for the Pentium III /
II / Celeron processor because it sends VID signals directly to the onboard power
controller.

3. H/W SETUP

Motherboard Settings

ASUS P2B-N User’s Manual 21

(This page was intentionally left blank.)

Motherboard Settings

3. H/W SETUP

3. HARDWARE SETUP

22 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

3.5 System Memory (DIMM)

NOTE: No hardware or BIOS setup is required after adding or removing memory.
This motherboard uses only Dual Inline Memory Modules (DIMMs). Sockets are

available for 3.3Volt (power level) unbuffered Synchronous Dynamic Random Ac-
cess Memory (SDRAM). One side (with memory chips) of the DIMM takes up one
row on the motherboard.

To utilize the chipset’s Error Checking and Correction (ECC) feature, you must use a
DIMM module with 9 chips per side (standard 8 chips/side + 1 ECC chip) and make
the proper settings through 4.5 Chipset Features Setup.

Memory speed setup is recommended through SDRAM Configuration in 4.5 Chipset

Features Setup.

Install memory in any combination as follows:

DIMM Location 168-pin DIMM Total Memory

Socket 1 (Rows 0&1) SDRAM 8, 16, 32, 64, 128, 256MB x1
Socket 2 (Rows 2&3) SDRAM 8, 16, 32, 64, 128, 256MB x1

Total System Memory (Max 512MB) =

NOTE: At the time this User’s Manual was written, 256MB DIMMs are only avail-

able as registered memory.

3.5.1 General DIMM Notes

• For the system CPU bus to operate at 100MHz, use only PC100-compliant
DIMMs. When this motherboard operates at 100MHz, most system will not

even boot if non-compliant modules are used because of the strict timing issues
involved under this speed. If your DIMMs are not PC100-compliant, set the
CPU bus frequency (FS) to 66MHz RAM to ensure system stability.

• ASUS motherboards support SPD (Serial Presence Detect) DIMMs. This is the
memory of choice for best performance vs. stability.

• Two possible memory chips are supported: SDRAM with and without ECC.

• SDRAM chips are generally thinner with higher pin density than EDO (Ex­tended Data Output) chips.

• BIOS shows SDRAM memory on bootup screen.

• Single-sided DIMMs come in 16, 32, 64,128MB; double-sided come in 32, 64,
128, 256MB.

3. H/W SETUP

System Memory

ASUS P2B-N User’s Manual 23

3. HARDWARE SETUP

o

3.5.2 DIMM Memory Installation

Insert the module(s) as shown. Because the number of pins are different on either
side of the breaks, the module will only fit in the orientation shown. DRAM SIMM
modules have the same pin contacts on both sides. SDRAM DIMMs have different
pin contacts on each side and therefore have a higher pin density.

20 Pins

System Memory

3. H/W SETUP

P2B-N 168-pin DIMM Memory Sockets

The DIMMs must be 3.3Volt unbuffered SDRAMs. To determine the DIMM type,
check the notches on the DIMMs (see figure below).

168-Pin DIMM Notch Key Definitions (3.3V)

60 Pins

®

88 Pins

L

DRAM Key Position

RFU

Buffered

Unbuffered

Voltage Key Position

5.0V

Reserved

3.3V

The notches on the DIMM will shift between left, center, or right to identify the type
and also to prevent the wrong type from being inserted into the DIMM slot on the
motherboard. You must tell your retailer the correct DIMM type before purchasing.
This motherboard supports four clock signals per DIMM.

24 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

3.6 Central Processing Unit (CPU)

NOTE: The following pictures are provided for reference purposes only. The ap­pearance of your retention mechanism and fan may be different from the following
examples.

Your motherboard provides a Slot 1 connector for a Pentium
aged in a Single Edge Contact Cartridge (SECC2), a Pentium

®

III processor pack-

®

II processor pack­aged in SECC2/SECC, or a Celeron™ processor packaged in a Single Edge Proces­sor Package (SEPP). An ASUS S370 CPU card can allow Socket 370 processors to
be used on any ASUS motherboard with the Slot 1 connector (See 7.2 S370 Series
CPU Cards for instructions on using this card).

Pentium II processor packaged in an SECC with
heatsink and fan (top view)

Pentium III (in an SECC2) with heatsink and fan
NOTE: The SEPP fan (for Celeron processors) is
similar to SECC2 fan except that the clamping
design is different.

3.6.1 Universal Retention Mechanism

Your motherboard comes preinstalled
with a Universal Retention Mechanism
(URM). The URM supports Pentium III /
II and Celeron processors.

CPU

3. H/W SETUP

Universal Retention Mechanism (URM)

3.6.2 Heatsinks

The recommended heatsinks (see section on recommended heatsinks for Pentium
III / II processors for more information) for the boxed Pentium III / II and Celeron
processors are those with three-pin fans that can be connected to the fan connectors
on the motherboard.

WARNING! Be sure that there is sufficient air circulation across the processor’s

heatsink by regularly checking that your CPU fan is working. W ithout sufficient
circulation, the processor could overheat and damage both the processor and the
motherboard. You may install an auxiliary chassis fan, if necessary.

ASUS P2B-N User’s Manual 25

3. HARDWARE SETUP

3.6.3 Installing the Processor

1. Unlock the URM’s Folding Support Arms:

The folding support arms of the URM are
locked when shipped.

T o unlock the support arms, simply flip them
up to an upright position.

Locked Folding
Support Arms

3. H/W SETUP

CPU

The URM is now ready for the installation

Unlocked Folding
Support Arms

of your processor.

2. Attach the Heatsink
NOTE: If provided, you should follow the heatsink attachment instructions

that came with your heatsink or processor. The following steps are provided
only as a general guide and may not reflect those for your heatsink.

Using the SECC fan with the Pentium

®

II

Lock Arm

Lock Arm

Push the two lock arms one direction to clamp
the heatsink onto the processor and the other
direction to release.

Using the SECC2 fan with the Pentium

®

III

Insert the four heatsink’s pins through the
holes of the SECC2. Place the metal clip on
the ends of the pins and slide until it locks
into place.

Four Pins and metal clip

NOTE: The SEPP heatsink and fan (for Intel Celeron processors) is similar to
the SECC2 heatsink and fan except that the clamping design is different.

26 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

W ARNING! Make sure the heatsink is mounted tightly against the SECC2, SECC,

or SEPP; otherwise, the CPU will overheat. You may install an auxiliary fan to
provide adequate circulation across the processor’s passive heatsink.

3. Insert the SECC2/SECC/SEPP
SECC with Pentium

®

II only: Push the SECC’s two locks inward until you hear

a click (the picture in step 2 shows the locks in the outward position and inward in
the picture below).

With the heatsink facing the motherboard’s chipset, push the SECC, SECC2, or
SEPP gently but firmly into the Slot 1 connector until it is fully inserted.

SECC

Push lock inward

CPU fan cable to
fan connector

SECC2/SEPP

CPU fan cable to
fan connector

4. Secure the SECC2/SECC/SEPP

CPU

3. H/W SETUP

Secure the SECC2/SECC/SEPP in place by pushing the SECC2/SECC/SEPP
until it is firmly seated on the Slot 1 connector.

SECC with Pentium

®

II only: The SECC locks should be outward when se-

cured so that the lock shows through the retention mechanism’s lock holes.

SECC SECC2/SEPP

Lock hole

Lock hole

CPU fan cable to
fan connector

CPU fan
cable to fan
connector

ASUS P2B-N User’s Manual 27

3. HARDWARE SETUP

3.6.4 ASUS Smart Thermal Solutions

(only with optional hardware monitor)
ASUS provides two smart solutions to Slot 1 CPU thermal problems: the ASUS

Smart Fan or ASUS S-P2FAN and the ASUS P2T -Cable.

3. H/W SETUP

CPU

ASUS S-P2FAN

The optional ASUS Smart Fan or ASUS S-P2FAN is a CPU
fan for a Pentium

®

II processor packaged in an SECC. Un-

Thermal Cable
(2 black wires)

CPU Fan Cable
(3 colored wires)

like other CPU thermal solutions, the ASUS S-P2FAN has
an integrated thermal sensor located near the center of the
CPU heat source. The sensor is optimized by ASUS to give
the most accurate reading of the CPU temperature, thus
provides the best protection to your computer system.

To Use the ASUS S-P2FAN

See 2. Attach the Heatsink on the preceding page for the relevant procedures. Note
that the S-P2FAN comes with a rock arm design for easy FAN/CPU installation.

ASUS P2T-Cable

The optional ASUS P2T-Cable can be
used for a Pentium

®

III/II processor pack-

Sensor

aged in an SECC2/SECC, or a Celeron™
processor packaged in an SEPP.

Sensor Connector Plug

NOTE: The ASUS P2T-Cable can
only be used in a Slot 1 motherboard
with a 2-pin thermal sensor connector.

To Use the ASUS P2T-Cable

NOTE: The following procedures assume that you have properly attached a
heatsink onto an SECC2/SECC/SEPP.

1. Simply peel off the tab from the sensor and then stick the sensor near the middle
edge of the Intel boxed processor heatsink with fan (middle) or to either the
upper or lower edge of the Celeron™ heatsink (right), as indicated.

Tab

Sensor

← OR STICK ABOUT HERE

28 ASUS P2B-N User’s Manual

3. HARDWARE SETUP

WARNING! Do not insert the sensor between the processor and heatsink, other-

wise, it will cause damage to the P2T-Cable.

IMPORTANT: ASUS guarantees accurate readings only for the ASUS Smart

Fan and the Intel boxed processor heatsink with fan because both have similar
heat distribution and heatsink material.

2. Connect the P2T -Cable to the CPU thermal sensor connector on the motherboard.

CPU THEM

R

P2B-N CPU Thermal Sensor Connector

3.6.5 Recommended Heatsinks for Slot 1 Processors

The recommended heatsinks for the Slot 1 processors are those with three-pin fans,
such as the ASUS Smart Fan, that can be connected to the motherboard’s CPU fan
connector . These heatsinks dissipate heat more efficiently and with an optional hard­ware monitor, they can monitor the fan’s RPM and use the alert function with the
Intel LANDesk Client Manager (LDCM) or the ASUS PC Probe software.

CPU

3. H/W SETUP

SECC Heatsink & Fan SECC2 Heatsink & Fan
NOTE: The SEPP heatsink and fan (for Intel Celeron processors) is similar to the

SECC2 heatsink and fan except that the clamping design is different.

ASUS P2B-N User’s Manual 29

3.7 Expansion Cards

WARNING! Unplug your power supply when adding or removing expansion

cards or other system components. Failure to do so may cause severe damage to
both your motherboard and expansion cards.

3.7.1 Expansion Card Installation Procedure

1. Read the documentation for your expansion card and make any necessary hard­ware or software settings for your expansion card, such as jumpers.

2. Remove your computer system’s cover and the bracket plate on the slot you
intend to use. Keep the bracket for possible future use.

3. Carefully align the card’s connectors and press firmly.

4. Secure the card on the slot with the screw you removed above.

Expansion Cards

3. H/W SETUP

5. Replace the computer system’s cover.

3. HARDWARE SETUP

6. Set up the BIOS if necessary
(such as IRQ xx Used By ISA: Yes in PNP AND PCI SETUP)

7. Install the necessary software drivers for your expansion card.

3.7.2 Assigning IRQs for Expansion Cards

Some expansion cards need to use an IRQ to operate. Generally, an IRQ must be
exclusively assigned to one use. In a standard design, there are 16 IRQs available
but most of them are already in use, leaving 6 IRQs free for expansion cards. If your
motherboard has PCI audio onboard, an extra IRQ will be used, leaving 5 IRQs
free. If your motherboard has ISA audio onboard, an extra 3 IRQs will be used,
leaving 3 IRQs free.

Both ISA and PCI expansion cards may require the use IRQs. System IRQs are
available to cards installed in the ISA expansion bus first, then any remaining IRQs
are available to PCI cards. Currently , there are two types of ISA cards. The original
ISA expansion card design, now referred to as legacy ISA cards, requires that you
configure the card’s jumpers manually and then install it in an available slot on the
ISA bus. To see a map of your used and free IRQs in Windows 98, the Control

Panel icon in My Computer, contains a System icon, which gives you a Device
Manager tab. Double-clicking on a specific hardware device gives you the Re-

sources tab which shows the Interrupt number and address. Make sure that no two
devices use the same IRQ or your computer will experience problems when those
two devices are in use at the same time.

ASUS P2B-N User’s Manual 30