Asus P2L97A User manual

R
P2L97A
Pentium®II Motherboard
USER’S MANUAL

ASUS P2L97A User’s Manual
2
USER’S NOTICE
Product Name: ASUS P2L97A
Manual Revision: 1.03
Release Date: November 1997
No part of this manual, including the products and software described in it, may be repro-
duced, 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 TO THE IMPLIED
WARRANTIES OR CONDITIONS OF MERCHANTABILITYOR FITNESS FORAPAR-
TICULAR PURPOSE. IN NO EVENT SHALL ASUS, ITS DIRECTORS, OFFICERS,
EMPLOYEES OR AGENTS BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDEN-
TAL, OR CONSEQUENTIAL DAMAGES (INCLUDING DAMAGES FOR LOSS OF
PROFITS, LOSS OF BUSINESS, LOSS OF USE OR DATA, INTERRUPTION OF BUSI-
NESS 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.
Products and corporate names appearing in this manual may or may not be registered trade-
marks 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.
• ATI and 3D RAGE are registered trademarks of ATI Technologies Inc.
• 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 board itself. Manual revisions
are released for each board 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.
Forprevious or updated manuals, BIOS,drivers, orproduct releaseinformation,contactASUS
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 FUR-
NISHED FOR INFORMATIONAL USE ONLY, AND ARE SUBJECT TO CHANGE AT
ANY TIME WITHOUT NOTICE, AND SHOULD NOT BE CONSTRUED AS A COM-
MITMENT BY ASUS. ASUS ASSUMES NO RESPONSIBILITY OR LIABILITY FOR
ANYERRORS OR INACCURACIESTHAT MAYAPPEARINTHIS MANUAL, INCLUD-
ING THE PRODUCTS AND SOFTWARE DESCRIBED IN IT.
Copyright © 1997 ASUSTeK COMPUTER INC. All Rights Reserved.

ASUS P2L97A User’s Manual 3
ASUS CONTACT INFORMATION
ASUSTeK COMPUTER INC.
Marketing Info
Address: 150 Li-Te Road, Peitou, Taipei, Taiwan 112, ROC
Telephone: [phone]
Fax: [phone]
Email: [email protected]
Technical Support
Fax: [phone]
BBS: [phone]
Email: [email protected]
WWW: www.asus.com.tw
Gopher: gopher.asus.com.tw
FTP: ftp.asus.com.tw/pub/ASUS
ASUS COMPUTER INTERNATIONAL
Marketing Info
Address: 721 Charcot Avenue, San Jose, CA 95131, USA
Telephone: [phone]
Fax: [phone]
Email: [email protected]
Technical Support
BBS: [phone]
Email: [email protected]
WWW: www.asus.com
ASUS COMPUTER GmbH
Marketing Info
Address: Harkort Str. 25, 40880 Ratingen, BRD, Germany
Telephone: [phone]
Fax: [phone]
Email: [email protected]
Technical Support
Hotline: [phone]
BBS: 49-2102-448690
Email: [email protected]
WWW: www.asuscom.de
FTP: ftp.asuscom.de/pub/ASUSCOM

ASUS P2L97A User’s Manual
4
CONTENTS
I. INTRODUCTION 7
How this Manual is Organized ........................................................... 7
Item Checklist ..................................................................................... 7
II. FEATURES 8
Features of the ASUS P2L97A Motherboard ..................................... 8
The ASUS P2L97A Motherboard ................................................. 9
III. INSTALLATION 10
Layout of the ASUS P2L97A Motherboard...................................... 10
Installation Steps............................................................................... 12
1. Jumpers ......................................................................................... 12
Jumper Settings ........................................................................... 13
2. System Memory (DIMM) ............................................................. 15
DIMM Memory Installation Procedures: .............................. 16
3. Central Processing Unit (CPU).................................................... 17
4. Expansion Cards ........................................................................... 21
Expansion Card Installation Procedure ................................. 21
Assigning IRQs for Expansion Cards.................................... 21
Assigning DMA Channels for ISA Cards.............................. 22
5. External Connectors...................................................................... 23
Power Connection Procedures .................................................... 29
IV. BIOS SOFTWARE 30
Support Software .............................................................................. 30
Flash Memory Writer Utility....................................................... 30
Advanced Features Menu ...................................................... 31
Managing and Updating Your Motherboard’s BIOS................... 32
6. BIOS Setup .................................................................................. 33
Load Defaults ........................................................................ 34
Standard CMOS Setup ................................................................ 34
Details of Standard CMOS Setup:......................................... 34

ASUS P2L97A User’s Manual 5
CONTENTS
BIOS Features Setup ................................................................... 37
Details of BIOS Features Setup............................................. 37
Chipset Features Setup ................................................................ 40
Details of Chipset Features Setup.......................................... 40
Power Management Setup........................................................... 43
Details of Power Management Setup .................................... 43
PNP and PCI Setup ..................................................................... 46
Details of PNP and PCI Setup ............................................... 46
Load BIOS Defaults .................................................................... 48
Load Setup Defaults .................................................................... 48
Supervisor Password and User Password ................................... 49
IDE HDD Auto Detection ........................................................... 50
Save & Exit Setup ....................................................................... 51
Exit Without Saving .................................................................... 51
V. DESKTOP MANAGEMENT 52
Desktop Management Interface (DMI)............................................. 52
Introducing the ASUS DMI Configuration Utility ................ 52
System Requirements ............................................................ 52
Using the ASUS DMI Configuration Utility ......................... 53
VI. ASUS PCI SCSI Cards 55
Symbios SCSI BIOS and Drivers ..................................................... 55
ASUS PCI-SC200 & PCI-SC860 SCSI Cards ................................. 55
Setting Up the ASUS PCI-SC200 & PCI-SC860........................ 56
Setting the INTAssignment for the ASUS PCI-SC200 .............. 56
Terminator Requirements for SCSI Devices ............................... 56
Terminator Settings for the ASUS PCI-SC860 ........................... 57
Terminator Settings for the ASUS PCI-SC200 ........................... 57
SCSI ID Numbers for SCSI Devices .......................................... 58
SCSI ID Priority .......................................................................... 58

ASUS P2L97A User’s Manual
6
FCC & DOC COMPLIANCE
FederalCommunicationsCommissionStatement
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 installa-
tion. 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 inter-
ference 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! The use of shielded cables for connection of the monitor to the
graphics card is required to assure compliance with FCC regulations. Changes
or modifications to this unit not expressly approved by the party responsible for
compliance could void the user's authority to operate this equipment.
CanadianDepartmentofCommunicationsStatement
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 Cana-
dian Department of Communications.

ASUS P2L97A User’s Manual 7
I. INTRODUCTION
I. INTRODUCTION
Manual / Checklist
How this Manual is Organized
This manual is divided into the following sections:
I. Introduction Manual information and checklist
II. Features Information and specifications concerning this product
III. Installation Instructions on setting up the motherboard
IV. BIOS Software Instructions on setting up the BIOS software
V. Desktop Management BIOS supported Desktop Management Interface
VI. ASUS SCSI Cards Installation of ASUS SCSI cards (optional)
Item Checklist
Please check that your package is complete. If you discover damaged or missing
items, please contact your retailer.
(1) ASUS motherboard
(1) Retention mechanism
(2) Attach mount bridges (factory installed)
(1) IDE ribbon cable for master and slave drives
(1) Floppy ribbon cable for (1) 5.25inch floppy and (2) 3.5inch floppies
(1) bag of spare jumpers
(1) disk or CD with support drivers and utilities:
• Flash Memory Writer utility to update the onboard programmable BIOS
• Desktop Management Interface (DMI) utility
• Readme files for descriptions and use of the files
• Technical Support Form
(1) User’s Manual
ASUS PCI-SC200 Fast-SCSI or PCI-SC860 Ultra-Fast SCSI Card (optional)

8ASUS P2L97A User’s Manual
Features of the ASUS P2L97A Motherboard
TheASUS P2L97Ais carefully designed for the discriminating PC user who wants
many features processed by the fastest CPU. This motherboard:
•Processor Support: Intel Pentium
®
II (233MHz–333MHz) processor.
•Intel Chipset: Features Intel’s 440LX AGPset with I/O subsystems.
•AGPChipset: Provides ATI 3D RAGE GraphicsAccelerator chipset, with on-
boardvideo controllerand 4MBof 64-bitSGRAM memory.AcceleratedGraphics
Port (AGP) features high performance, component level interconnectivity tar-
geted at 3D graphical display applications.
•AMC Connector: SupportsATI Multimedia Channel (AMC) for additional ca-
pabilities, such as optionalTV tuner card available for video capture, video cap-
ture, videophone, TV overlay, or TV tuner applications.
•Easy Installation: Supports autodetection of hard drives, PS/2 mouse, and Plug
and Play devices to make setup of hard drives, expansion cards, and other de-
vices virtually automatic.
•ISA & PCI Expansion Slots: Provides two 16-bit ISA and four 32-bit PCI slots.
•Super Multi-I/O: Provides one high-speed UART compatible serial port and one
parallel port with EPP and ECP capabilities.
• 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.) (See section V)
•CPU Built-In Level 2 Cache: 512KB or 256KB Pipelined Burst Level 2 cache
in the Pentium II Single Edge Contact (SEC) cartridge.
•Versatile Memory Support: Equipped with three DIMM sockets to support (8,
16, 32, 64, or 128MB) 168-pin SDRAM/EDO memory modules up to 384MB.
•PCI Bus Master IDE Controller: Comes with an onboard PCI Bus Master
IDE controller with two connectors that supports four IDE devices in two chan-
nels, supports PIO Modes 3 and 4 and Bus Master IDE DMA Mode 2, and
supports Enhanced IDE devices such as Tape Backup and CD-ROM drives.
Supports two drives of either 5.25-inch (360KB or 1.2MB) or 3.5-inch (720KB,
1.44MB, or 2.88MB) disk drives. Supports Japanese “Floppy 3 mode” (3.5-inch
disk drive: 1.2MB) and LS-120 floppy disk drives (3.5-inch disk drive: 120 MB,
1.44MB, 720K). BIOS supports IDE CD-ROM or SCSI device boot-up.
•Performance:528MB/s data transfer rate using SDRAM, 33MB/s IDE transfer
rate using Bus Master UltraDMA/33 IDE, concurrent PCI allows multiple PCI
transfers.
•SCSI Bios: Supports optional ASUS SCSI controller cards through onboard
SYMBIOS firmware.
II. FEATURES
Specifications
II. FEATURES

ASUS P2L97A User’s Manual 9
II. FEATURES
II. FEATURES
Motherboard Parts
The ASUS P2L97A Motherboard
USB Port 1 (Top)
USB Port 2 (Bottom)
VGA
(Bottom)
Multi-I/O and
Keyboard BIOS
4 PCI Slots
4MBSGRAM VGA
memory
2ISA Slots
PS/2 Mouse (Top)
PS/2 Keyboard (Bottom)
Parallel (Top)
DIMM Sockets
Intel 440LXAGPset
Floppy Disk
Drive Connector
SEC CPU Slot
COM 1
(Bottom)
Intel PIIX4
PCIset
Primary/Secondary
IDE Connectors
OnboardATIAGP
VGAChipset
Programmable
Flash EEPROM

10 ASUS P2L97A User’s Manual
III. INSTALLATION
Layout of the ASUS P2L97A Motherboard
Floppy Disk Drives
Secondary IDE
Primary IDE
Infrared (IrDA)
Intel PIIX4
PCIset
PCI Slot 1
PCI Slot 2
PCI Slot 3
PCI Slot 4
ISA Slot 1
ISA Slot 2
CMOS Power
(CR2032 3V
Lithium Cell)
Single Edge Contact Slot
Intel
440LX
AGPset
ATX Power Connector
AMC Port
DIMM Socket 2 (64-bit, 168-pin module)
DIMM Socket 3 (64-bit, 168-pin module)
23 45
DIMM Socket 1 (64-bit, 168-pin module)
01Row
FAN1
1MB SGRAM
(onboard VGA
memory option)
Onboard
ATI AGP
VGA
Chipset
USB
PS/2
USB 1 (TOP PORT)
USB 2 (BOTTOM)
MOUSE (TOP PORT)
KEYBOARD (BOTTOM)
VGA
COM 1
PARALLEL PORT
Panel Connectors
FS0
FS1
FS2
BUS Freq.
Freq. Ratio
BF3
BF2
BF1
BF0
IDELED
Keyboard
BIOS &
Multi-I/O
Chip
Flash EEPROM
(Programable BIOS)
1MB SGRAM
(onboard VGA
memory option)
1MB SGRAM
(onboard VGA
memory option)
1MB SGRAM
(onboard VGA
memory option)
CLRTC
VIRQ.
R
Wake on LAN
Board Layout
III. INSTALLATION

ASUS P2L97A User’s Manual 11
III. INSTALLATION
Jumpers
1) CLRTC p. 13 Real Time Clock (RTC) (Short/Clear CMOS)
2) VIRQ p. 13 VGA Interrupt Selection
3) FS0, FS1, FS2 p. 14 CPU Bus Frequency
4) BF0, BF1, BF2, BF3 p. 14 CPU Core:Bus Frequency Multiple
Expansion Slots/Sockets
1) DIMM Sockets p. 15 DIMM Memory Module Support
2) SEC CPU Slot p. 15 Single Edge Contact CPU Support
3) SLOT1, SLOT2 p. 21 16-bit ISA Bus Expansion Slots
4) PCI1, PCI2, PCI3, PCI4 p. 21 32-bit PCI Bus Expansion Slots
Connectors
1) PS2KBMS p. 23 PS/2 Keyboard Connector (6-pin Female)
2) PS2KBMS p. 23 PS/2 Mouse Connector (6-pin Female)
3) PRINTER p. 24 Parallel (Printer) Port Connector (25-pin Female)
4) COM1 p. 24 Serial Port COM1 (One 9-pin Male)
5) VGA p. 24 Monitor (VGA) Output Connector (15-pin Female)
6) USB p. 25 Universal Serial BUS Ports 1 & 2 (two 4-pin Female)
7) FLOPPY p. 25 Floppy Drive Connector (34-1 pin block)
8) FAN1 p. 25 CPU Fan Power Lead (3 pins)
9) PRIMARY/SECOND. IDE p. 26 Primary / Secondary IDE Connector (40-1 pin blocks)
10) IDELED p. 26 IDE LED Activity Light (2 pins)
11) WOL_CON p. 26 Wake On LAN Connector (3 pins)
12) IR p. 27 Infrared Port Module Connector (5 pins)
13) ATXPWR p. 27 ATX Motherboard Power Connector (20-pin block)
14) MSG.LED (PANEL) p. 28 LED Lead (2 pins)
15) SMI (PANEL) p. 28 SMI Switch Switch Lead (2 pins)
16) PWR.SW (PANEL) p. 28 ATX Power Switch / Soft Power Switch (2 pins)
17) RESET (PANEL) p. 28 Reset Switch Lead (2 pins)
18)
PWR LED ( PANEL ) p. 28 System Power LED Lead (3 pins)
19) SPEAKER (PANEL) p. 28 Speaker Connector (4 pins)
Board Layout
III. INSTALLATION

12 ASUS P2L97A User’s Manual
III. INSTALLATION
Jumpers
III. INSTALLATION
Installation Steps
Before using your computer, you must complete the following steps:
1. Set Jumpers
2. Install DRAM Modules
3. Install the Central Processing Unit (CPU)
4. Install Expansion Cards
5. Connect Ribbon Cables, Cabinet Wires, and Power Supply
6. Setup the BIOS Software
1. Jumpers
Several hardware settings are made through the use of jumper caps to connect jumper
pins (JP) on the motherboard. See motherboard layout on page 10 for locations of
jumpers. The jumper settings will be described numerically such as [----], [1-2],
[2-3] for no connection, connect pins 1&2, and connect pins 2&3 respectively. Pin 1
for our motherboards is always on top
Pin 1
or on the left
Pin 1
when holding the
motherboard with the keyboard connector away from yourself. A “1” is written be-
sides pin 1 on jumpers with three pins. The jumpers will also be shown graphically
such as to connect pins 1&2 and to connect pins 2&3. Jumpers with
two pins will be shown as for Short (On) and for Open (Off). For manufac-
turing simplicity, the jumpers may be sharing pins from other groups. Use the dia-
grams in this manual instead of following the pin layout on the board. Settings with
two jumper numbers require that both jumpers be moved together. To connect the
pins, simply place a plastic jumper cap over the two pins as diagramed.
WARNING! Computer motherboards and expansion cards contain very delicate
Integrated Circuit (IC) chips. To protect them against damage from static electric-
ity, 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 or
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.

ASUS P2L97A User’s Manual 13
III. INSTALLATION
III. INSTALLATION
Jumpers
Jumper Settings
1. Real Time Clock (RTC) RAM (CLRTC)
The CMOS RAM is powered by the onboard button cell battery. To clear the
RTC data: (1) Turn off your computer and unplug yourAC power, (2) Short the
two points (Labeled: CLRTC), (3) Turn on your computer, (4) Hold down
<Delete> during bootup and enter BIOS setup to re-enter user preferences.
Short small solder points to clear CMOS
CLRTC
2. VGA Interrupt Selection (VIRQ)
These jumpers allow you to set the VGA interrupt method. The default disables
the chipset’s interrupt routing. Some video capture cards may require that inter-
rupts be assigned by the onboard chipset.
Disable (Default) Enable
VIRQ VIRQ

14 ASUS P2L97A User’s Manual
III. INSTALLATION
Jumpers
III. INSTALLATION
CPU Bus Frequency
CPU Core:Bus Frequency Ratio
5.0x(5/1)4.5x(9/2)4.0x(4/1)3.5x(7/2)2.0x(2/1)
BF2 BF3 BF1 BF0
1
2
3
BF2 BF3 BF1 BF0
1
2
3
BF2 BF3 BF1 BF0
1
2
3
BF2 BF3 BF1 BF0
1
2
3
BF2 BF3 BF1 BF0
1
2
3
83MHz
FS0 FS1 FS2
1
2
3
75MHz
FS0 FS1 FS2
1
2
3
66MHz
FS0 FS1 FS2
1
2
3
60MHz
FS0 FS1 FS2
1
2
3
3. CPU Bus Frequency (FS0, FS1, FS2)
This option tells the clock generator what frequency to send to the CPU.This allows the
selection of the CPU’s External frequency (or BUS Clock). The BUS Clock multiplied
by the BUS Ratio equals the CPU’s Internal frequency (the advertised CPU speed).
4. CPU Core:BUS Frequency Multiple (BF0, BF1, BF2, BF3)
This option sets the frequency ratio between the Internal frequency of the CPU
and the CPU’s External frequency. These must be set in conjunction with theCPU
Bus Frequency.
Set the jumpers by the Internal speed of your processor as follows:
(BUS Freq.) (Freq. Ratio)
CPU Model Freq. Ratio BUS F. FS0 FS1 FS2 BF0 BF1 BF2 BF3
Intel Pentium II 300MHz 4.5x 66MHz [1-2] [1-2] [1-2] [1-2] [2-3] [1-2] [2-3]
Intel Pentium II 266MHz 4.0x 66MHz [1-2] [1-2] [1-2] [2-3] [2-3] [1-2] [2-3]
Intel Pentium II 233MHz 3.5x 66MHz [1-2] [1-2] [1-2] [1-2] [1-2] [2-3] [2-3]
NOTES:Overclocking your processor is not recommended. It may result in a slower
speed. Voltage Regulator Output Selection (VID) is not needed for the Pentium II
processor because it sends a VID signal directly to the onboard power controller.
WARNING!Frequencies above 66Mhz exceed the specifications for the onboard
Intel Chipset and are not guaranteed to be stable.
Intel Pentium II Processor in an SEC Cartridge
(233-333MHz 256/512KB L2 Cache)

ASUS P2L97A User’s Manual 15
2. System Memory (DIMM)
Only Dual Inline Memory Modules (DIMM’s) can be used with this motherboard.
Four socketsare availablefor 3.3Volt(powerlevel) Unbuffered SynchronousDRAMs
(SDRAM) or EDO DRAM of either 8, 16, 32, 64, or 128MB to form a memory size
between 8MB to 512MB. One side (with memory chips) of the DIMM module 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 parity chip) and
make the proper settings in the BIOS Chipset Features Setup.
IMPORTANT: Memory speed setup is required through “Auto Configuration” in
BIOS Chipset Features Setup.
Parity EDO DIMM (9 chips)
Non-Parity SDRAM DIMM (8 chips)
General DIMM Notes: (not true for all memory modules)
• Four possible memory chips are supported: EDO or SDRAM with and without parity.
• SDRAM chips are generally thinner with higher pin density than EDO chips.
• BIOS shows EDO or SDRAM memory on bootup screen.
• 8 chip/side modules do not support parity, only 9 chip/side modules support parity.
• Single sided modules are usually 16 or 64 MB, double sided are usually 8, 32, or 128MB.
ASUS Memory Examples:
III. INSTALLATION
III. INSTALLATION
System Memory
Install memory in any combination as follows:
DIMM Location 168-pin DIMM Memory Modules Total Memory
Socket 0 (Rows 0&1) SDRAM/EDO 8, 16, 32, 64, 128MB x1
Socket 1 (Rows 2&3) SDRAM/EDO 8, 16, 32, 64, 128MB x1
Socket 2 (Rows 4&5) SDRAM/EDO 8, 16, 32, 64, 128MB x1
Total System Memory (Max 384MB) =

16 ASUS P2L97A User’s Manual
III. INSTALLATION
System Memory
III. INSTALLATION
DIMM Memory Installation Procedures:
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 as shown. DRAM
SIMM modules have the same pin contact on both sides. SDRAM DIMM modules
have a different pin contact on each side and therefore have a higher pin density.
168 Pin DIMM Memory Sockets
88 Pins
20 Pins 60 Pins
Lock
The Dual Inline Memory Module (DIMM) memory modules must be 3.3Volt Un-
buffered Synchronous DRAM (SDRAM) or Extended Data Output (EDO) . You
can identify the type of DIMM module by the illustration below:
168-Pin DIMM Notch Key Definitions (3.3V)
DRAM Key Position Voltage Key Position
Unbuffered
RFU
Buffered Reserved
3.3V
5.0V
The notch on the DIMM module will shift between left, center, or right to identify
the type and also to prevent the wrong type to be inserted into the DIMM slot on the
motherboard. You must ask your retailer for the specifications before purchasing.
Four clock signals are supported on this motherboard.

ASUS P2L97A User’s Manual 17
III. INSTALLATION
3. Central Processing Unit (CPU)
The following items should have been included with your motherboard:
Pentium II Retention
Mechanism
Lock Holes
Captive Nut
Attach Mount Bridges
(Factory Installed) Heatsink Support Base/Top Bar
(for Passive Heatsink)
Top Bar
Base
Posts
Pin
The following items must be purchased separately fromASUS or a third party vendor:
AAVID Heatsink
Elan Vital Heatsink
Pentium II Processor Passive Heatsink
Heatsink bottom Groove
for the Support Top Bar
Larger Fin should
be on the bottom.
The heatsinks shown are only recommendations. Check with your vendor for other
compatible heatsinks if you wish. The procedures shown in this manual are for in-
stalling the AAVID heatsink with fan. The procedures for installing the Elan Vital
heatsink withfan isalsosimilar asthat fortheAAVID heatsink.The ElanVital heatsink,
however, comes with a lever to clamp the heatsink into the SEC cartridge. Mount the
heatsink in the orientation shown then flip the lever from “Unlock” to “Lock.”
WARNING! Be sure that sufficient air circulation is available across the
processor’s heatsink by regularly checking that your CPU fan is working. With-
out sufficient circulation, the processor could overheat and damage both the pro-
cessor and the motherboard. You may install an auxiliary fan, if necessary.
Intel Pentium II Processor in an SEC Cartridge
(233–333MHz 256/512KB L2 Cache)
CPU
III. INSTALLATION

18 ASUS P2L97A User’s Manual
III. INSTALLATION
The Motherboard As Shipped
The ASUS P2L97A is shipped with the attach mount bridges already installed.
Lock holes
Captive nut
Captive nut
Installing the Pentium II Processor
1. Mount the Pentium II Retention Mechanism: The retention mechanism is
designed to fit into the SEC slot only one way. Be sure to align the notch in the
mechanism with the small rib on one side of the slot and that the mechanism is
properly seated on the board. Then, screw the captive nuts in place.
TIP: Orient the mechanism’s lock holes toward the motherboard’s chipset (see
motherboard layout for the location of the Intel 440LX AGPset).
WARNING! Do not overtighten the captive nuts. Doing so could damage your
motherboard. Tighten captive nuts to no more than 6±1 inch/pound.
NOTE: Encircled items are points where the
attach mount bridges are factory-installed
SEC slot for the
Pentium II processor
CPU
III. INSTALLATION

ASUS P2L97A User’s Manual 19
CPU
III. INSTALLATION
2. Mount the Heatsink: Place the SEC cartridge face down on a flat surface and lay
the heatsink flush on the back (metal side) of the SEC cartridge. Be sure that the
heatsink is firmly pressed against the SEC cartridge. When correctly installed,
no light must be showing through between the thermal pad of the heatsink and
the SEC cartridge.
WARNING! If the heatsink is not mounted tightly against the SEC cartridge,
the CPU will overheat. You may install an auxiliary fan to provide adequate
circulation across the processor’s passive heatsink.
SEC Cartridge with Heatsink (Top View)
Push each end of the clamps until they lock
The thermal pad & SEC cartridge should not have a gap!
Lock
Lock
3. Insert the SEC Cartridge: Push the SEC cartridge’s two locks inward (the
preceding picture shows the locks in the outward position and inward in the
picture below). With the heatsink facing the motherboard’s chipset, press the
cartridge gently but firmly until it is full inserted.
Push lock inward
III. INSTALLATION

20 ASUS P2L97A User’s Manual
III. INSTALLATION
4. Secure the SEC Cartridge: Secure the SEC cartridge in place by pushing the
SEC cartridge locks outward so that the lock shows through the retention
mechanism’s lock holes.
CPU
III. INSTALLATION