Motherboard Review - Asus P/I-P55T2P4 rev. 3.0 and 3.10


Recent informations about problems with this board could not be duplicated by me, the problem seems to be of minor nature and is easy to be remedied. The reason why one of my sponsors is publishing a negative image about this board seems to be more of political nature and is disapproved by me.

Features And Specifications


  • Intel 82430HX chipset, Revision 03, consisting of
  • 82439HX System Controller82371SB PCI I/O IDE Xcelerator


Socket: Socket 7

Supported CPUs:

  • Intel Pentium Classic, P54C, 75 - 200 MHz
  • Intel Pentium with MMX, P55C
  • Cyrix/IBM 6x86 120+ - 166+, revision 2.7 or later required (testing of c't-Magazine has shown, that rev. 2.6 is running also without problems)
  • Cyrix/IBM 6x86 P200+, so far only unofficially, but testing of c't-Magazine has shown, that it's running fine
  • Cyrix/IBM M2, so far unofficially, but board offers required voltage of 2.9 V
  • AMD K5 PR90 - PR100, probably the new ones just as well - will try to get a statement from Asus

Supported CPU Voltages:

  • STD 3.3 V
  • VRE 3.4 - 3.6 V
  • 2.5 V
  • 2.6 V
  • 2.7 V
  • 2.8 V
  • 2.9 V
  • Automatic detection of single or split voltage.

Supported Multiplier Settings:

  • x1.5, x2, x2.5, x3 for Intel Pentium CPUs
  • x2, x3 for Cyrix/IBM 6x86 CPUs

Supported Bus Speeds:

  • 50 MHz
  • 55 MHz
  • 60 MHz
  • 66 MHz
  • 75 MHz
  • 83 MHz
  • (100 MHz) - not verified

Second Level Cache

Pipelined Burst Static RAM Cache

  • 0 kB onboard, 0 kB in COAST slot
  • 256 kB onboard, 0 kB in COAST slot
  • 512 kB onboard, 0 kB in COAST slot
  • 0 kB onboard, 256 kB in COAST slot
  • 0 kB onboard, 512 kB in COAST slot

COAST modules have to meet the specifications of

  • Asus CM1 Rev. 1.6
  • Asus CM1 Rev. 3.0
  • COAST 2.0
  • COAST 2.1
  • COAST 3.0
  • COAST 3.1

Default of 64 MB cacheable RAM, upgradeable to 512 MB cacheable RAM by installation of 16K8 5V 15ns Tag RAM chip in provided DIL socket.


4 72 pin SIMM slots

supports ECC

RAM types supported:

  • FPM RAM with and without parity
  • EDO RAM with and without parity

RAM sizes supported:

  • 4 MB SIMM
  • 8 MB SIMM
  • 16 MB SIMM
  • 32 MB SIMM
  • 64 MB SIMM

Don't use SIMMs with more than 24 chips.


4 PCI slots, 2 full length

running at busclck/2
PCI specification 2.1

Asus Media Bus

for Asus Media Bus Revision 2.0 cards only

shared with PCI slot 4


3 ISA Slots, 3 full length, one shared with PCI slot 4

Super I/O

  • 1 Floppy Port (up to 2.88 MB, Japan 3 Mode Floppy Supported)
  • 2 Serial Ports (16550 Fast UART Compatible)
  • 1 Parallel Port (ECP, EPP Port)
  • IrDA TX/RX Header (= infra red port support)
  • PS/2 Mouse connector
  • USB connector

IDE Controller

2 x PCI Bus Master IDE ports (up to 4 IDE devices)


  • PIO Mode 3 & 4
  • DMA Mode 2


Award Plug&Play BIOS, tested with revision 1.08, flashable

supports bootable CDROM and bootable SCSI HDD, even if IDE HDD present
includes NCR SCSI BIOS for use with Asus PCI-SC200 SCSI controller card

Coming With

  • 2 serial port ribbon cables, attached to a mounting bracket
  • 1 parallel ribbon cable with mounting bracket
  • 1 IDE ribbon cable
  • 1 floppy ribbon cable
  • floppy disk with
  • Bus Master IDE Driver for Windows95, OS/2, WindowsNTDMI configuration utilityBIOS Flash programlatest Flash BIOS (1.07 in my case)

Coming Without

PS/2 Mouse connector cable


Good quality! That's what I'm expecting a manual to be like!


Ctcm Benchmark Results

The bus speeds 50, 55 and 60 MHz would all run at the fastest timing settings. Higher bus speeds, however, required the tuning of the BIOS timing settings. I've hence been distinguishing between the fastest settings, which ctcm would run at and the settings, which Windows 95 would run Winstone 96 flawlessly at. For everybody, who is using Windows 95 or who wants to be safe, the 'Windows 95 setting' results are the only ones that are realistical and really interesting, because they are the ones to certainly be free from crashes due to memory timing problems at these high bus speeds.

Swipe to scroll horizontally
Bus Speed [MHz]L2 Cache Speed [MB/s]Main Memory Speed [MB/s]DOS Simulation Speed [MB/s]Windows Simulation Speed [MB/s]
66(max timing)67.345.273.360.1
66(Windows 95 setting)67.344.273.359.4
75(max. timing)75.750.982.567.7
75(Windows 95 setting)75.749.782.566.9
83(max. timing)84.255.391.874.3
83(Windows 95 setting)

Other Benchmark Results

Swipe to scroll horizontally
CPU Speed / Bus Speed [MHz]Winstone 97Quake Timedemo
171/68 (turbo)37.715.0
205/68 (turbo)39.816.0

This board is slightly slower than the ABIT IT5H at the same speed, but the fastest setting amongst the above still is the 83 MHz bus speed setting at 166 MHz. It is even faster than 205/68.

Advantages & Disadvantages

The Advantages of the Asus P/I-P55T2P4

  • 75 and 83 MHz bus speed ability - this feature is unique at present!!
  • overclocking friendly
  • well equipped
  • supporting up to 512 MB cacheable RAM area optionally
  • P55C support
  • coming with Bus Master Drivers on floppy disk
  • good quality
  • high reliability
  • excellent web site, with lots of technical info too
  • good support
  • easy access to Flash BIOS upgrades

The Disadvantages Of The Asus P/I-P55T2P4

  • only four SIMM slots
  • only 3 ISA slots
  • Tag RAM chip for 512 MB cacheable RAM is not supplied by default
  • the ATX version of this board only supports max. 66 MHz bus speed
  • board still doesn't come with PS/2 Mouse adapter cable by default
  • due to the 430HX chipset, it doesn't support the superior SDRAM
  • manojvarughese
    I need to know where the CMOS battery is located?
  • manojvarughese
    It's an attempt to completely refurbish this ancient PC...need to boot from CD-ROm to install Win 98se...I'm not able to change the boot sequence to CD-ROM...