Introduction
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.
Chipset
- Intel 82430HX chipset, Revision 03, consisting of
- 82439HX System Controller
- 82371SB PCI I/O IDE Xcelerator
CPU
Socket: Socket 7
Supported CPUs:
- Intel Pentium Classic, P54C, 75 – 200 MHz
- Intel Pentium with MMX, P55C
- Cyrix/IBM 6×86 120+ – 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 6×86 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 6×86 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.
RAM
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.
PCI Bus
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
ISA Bus
3 ISA Slots, 3 full length, one shared with PCI slot 4
Super I/O
- 1 Floppy Port (up to 2.88MB, 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)
Support:
- PIO Mode 3 & 4
- DMA Mode 2
BIOS
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, WindowsNT
- DMI configuration utility
- BIOS Flash program
- latest Flash BIOS (1.07 in my case)
Coming without
PS/2 Mouse connector cable
Manual
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.
Bus Speed [MHz] | L2 Cache Speed [MB/s] | Main Memory Speed [MB/s] | DOS Simulation Speed [MB/s] | Windows Simulation Speed [MB/s] |
50 | 50.2 | 33.8 | 54.8 | 45.0 |
55 | 55.3 | 37.3 | 60.4 | 49.6 |
60 | 60.3 | 40.6 | 65.8 | 54.1 |
66 | 67.3 | 45.2 | 73.3 | 60.1 |
66 | 67.3 | 44.2 | 73.3 | 59.4 |
75 | 75.7 | 50.9 | 82.5 | 67.7 |
75 | 75.7 | 49.7 | 82.5 | 66.9 |
83 | 84.2 | 55.3 | 91.8 | 74.3 |
83 | 84.2 | 52.1 | 91.6 | 72.4 |
Other Benchmark Results
CPU Speed / Bus Speed [MHz] | Winstone 97 | Quake Timedemo |
166/66 | 37.3 | 14.7 |
166/83 | 40.0 | 16.9 |
171/68 (turbo) | 37.7 | 15.0 |
187.5/75 | 39.9 | 16.5 |
200/66 | 39.2 | 15.6 |
205/68 (turbo) | 39.8 | 16.0 |
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
Tips and Comments
Recommended BIOS Timing Settings for the Different Bus Speeds
a) 50, 55 and 60 Mhz Bus Speed
Jumper settings for 50 MHz bus speed (JP10-JP9-JP8):
Jumper settings for 55 MHz bus speed (JP10-JP9-JP8):
Jumper settings for 60 MHz bus speed (JP10-JP9-JP8):
If you should be running this board at these bus speeds (which I consider as pretty sad), you can max out the BIOS timing settings totally:
Auto Configuration | Disabled |
DRAM Read Burst Timing | x222 |
DRAM Write Burst Timing | x222 |
RAS to CAS Delay | 2T |
DRAM R/W Leadoff Timing | 6T/5T |
DRAM Turbo Read Leadoff | Enabled |
DRAM Speculative Leadoff | Enabled |
Turn-Around Insertion | Disabled |
Turbo Read Pipelining | Enabled |
b) 66 MHz Bus Speed
Jumper settings for 66 MHz bus speed (JP10-JP9-JP8):
Jumper settings for 68 MHz bus speed (JP10-JP9-JP8):
, this is the so called ‘turbo frequency’ bus speed known from Abit motherboards.
I’ve been able to run Quake at this Bus Speed completely without any change to the above, however the below configuration is the safe configuration for Windows 95. You anyway won’t notice any performance difference even in Quake, with Turbo Read Leadoff disabled or enabled.
Auto Configuration | Disabled |
DRAM Read Burst Timing | x222 |
DRAM Write Burst Timing | x222 |
RAS to CAS Delay | 2T |
DRAM R/W Leadoff Timing | 6T/5T |
DRAM Turbo Read Leadoff | Disabled |
DRAM Speculative Leadoff | Enabled |
Turn-Around Insertion | Disabled |
Turbo Read Pipelining | Enabled |
c) 75 MHz Bus Speed
Jumper settings for 75 MHz bus speed (JP10-JP9-JP8):
This again is the Windows 95 save setting. You might howeverhave to change the Leadoff Timing to 7T/6T instead, in caseyou’re occuring crashes or lockups in Windows 95. Another causefor trouble could be your EIDE interface. If you can’t get ridoff strange lockups, try to change your PIO mode settings to 3instead of Auto. This btw won’t make your HDD any slower at all,so don’t worry.
Auto Configuration | Disabled |
DRAM Read Burst Timing | x222 |
DRAM Write Burst Timing | x222 |
RAS to CAS Delay | 2T |
DRAM R/W Leadoff Timing | 6T/5T |
DRAM Turbo Read Leadoff | Disabled |
DRAM Speculative Leadoff | Enabled |
Turn-Around Insertion | Disabled |
Turbo Read Pipelining | Disabled |
d) 83 MHz Bus Speed
Jumper settings for 83 MHz bus speed (JP10-JP9-JP8):
I’ve been fiddeling with these settings a whole lot and the automatic 60 ns DRAM setting is by far the safest, especially for Windows95. I would also like to note, that the displayed timing settings, which are chosen automatically, are actually NOT reflecting the real settings. The real settings must be quite a bit faster, because you get a much slower main memory speed, if you choose the very same settings manually. Additionally I had to change the PIO mode of my HDDs to Mode 3 or even Mode 2. A test run with Winbench 96 was still showing a Diskmark of 1250 though.
Auto Configuration | 60ns DRAM |
DRAM Read Burst Timing | x222 |
DRAM Write Burst Timing | x333 |
RAS to CAS Delay | 3T |
DRAM R/W Leadoff Timing | 6T/5T |
DRAM Turbo Read Leadoff | Disabled |
DRAM Speculative Leadoff | Enabled |
Turn-Around Insertion | Disabled |
Turbo Read Pipelining | Disabled |
A Few Comments
The automatic ’60ns DRAM’ timing setting in the BIOS timing section of the setup is actually using different and faster settings than displayed!!
Overclocking seems to be somewhat more difficult than with my previous P/I-P55TP4XEG board. It has been tough, to get Windows 95 running stable at the 187.5 MHz CPU clock, I’m not really sure about the stability at o/c to 200 MHz and I’ve never been able to finish Winstone 96 at 208 MHz.
As you can see, there are a few bus speed jumper settings left, which can lead you to even more different bus speeds. One setting wouldn’t let my system even boot, regardless of the multiplier setting. I would imagine, that this is the setting for a bus speed of 100 MHz.
Summary
First of all, as you all know, I have to name the ability to run this HX board at 75 and even 83 MHz bus speed!! It makes this board to a one of a kind and it will be the reason for the huge success, this board will earn. It’s funny enough, because it’s actually no big deal, to supply a motherboard with a timer chip, that can produce all these bus speeds. I don’t think, that Asus is having any more procuction costs due to this timer chip. It only shows, that at last one motherboard manufacturer either has had the guts to stand up against Intel, who certainly dislike this new bus speed ability, or that Asus is the first company to see, how much we users out here are into tuning of our hardware. Which ever reason has been leading Asus’ decision for the higher multiplier settings, we have to thank Asus to give us the ability to reach new performance heights due to these new settings. It won’t be of any damage to Asus, that much is sure. I’m certain that either already now, or within a short while, this board will be the best seller of all Pentium boards. We can only hope, that the other motherboard manufacturers, who are enviously looking at this page, have got the message by now. I’d like to name Tyan and Supermicro in particular. These two successful motherboard manufacturers have been pathetic enough, to leave us dumb and unable to achieve any bus speeds above 66 MHz on their boards. Maybe only to please Intel. The ones, who HAVE to be pleased however are we, the stupid little computer users and customers. As soon as the sales go down for Tyan and Supermicro, they will learn, that taking us for brain dead is not the right way to go. I wonder, how long it will take, until Tyan and Supermicro will produce motherboards with 75 and 83 MHz bus speed too. Maybe they even will have the guts, to supply me with some of their motherboards for testing then.
I am recommending this motherboard without any restrictions. I am running my system at 166/83 now for a week and it is rock solid. As long as you adjust the RAM timing to sensible values, you won’t have any problems with it. I am missing more than 4 SIMM slots though, because so far I only could get 45ns EDO in 8MB SIMMs, which leaves me without any expansion space for my RAM. Other than that I’m entirely satisfied with this board and it will stay in my system until a considerably faster board should come out, that is as reliable as this Asus motherboard.
I would again like to stress, that the ATX version of this board P/I-XP55T2P4 does NOT support any bus speed higher than 66 MHz, and the upcoming revision 3 of this board doesn’t either. To my knowledge the VX chipset board P/I-P55TVX4 only supports up to 75 MHz bus speed.
Finally a little side note for you. I’ve recently heard the rumor, that Intel is planning a Pentium Classic at 225 and 250 MHz. Doesn’t this sound familiar? Maybe I’ve been spoiling the surprise, Intel wanted to offer us by releasing a P225 and P250 and announcing the birth of 75 and 83 MHz bus speed. Maybe this is the reason, why the P/I-P55T2P4 is supporting these bus speeds already. ?????? Well, but it is only a rumor…. ;-).
Related Links
ASUS Home WWW Server, frame free version
ASUS P/I-P55T2P4 Specification
ASUS FTP BIOS Beta versions, only for fearless cracks