by Anand Lal Shimpi on April 18, 1998 2:02 PM EST
We often find success in the most obscure places, while the world was expecting reliable operation at the 133MHz bus speed from ABIT and AOpen, it turns out that what the Overclocking Community wished for won't happen with current SDRAM that is...or so we thought.  DFI, made popular by their VLSI and VP3 Socket-7 motherboard solutions of 1996 - 1997 has stepped forward once again with a feature unmatched by the competition at the moment.  The DFI P2XBL, DFI's newly released 440BX motherboard, uses the Serial Presence Detect on PC100 Compliant SDRAM modules to Auto-configure itself for an operational 133MHz bus speed setting! 

Anand Tech Report Card Rating

Motherboard Specifications

CPU Interface Slot-1
Chipset Intel 440BX
L2 Cache N/A (on-chip)
Form Factor ATX
Bus Speeds 50 /66 / 75 / 83 / 100 / 103 / 112 / 133 MHz
Clock Multipliers 2.0x - 8.0x
Voltages Supported 1.3v - 3.5v (Auto-Detect)
Memory Slots 3 168pin DIMM Slots (EDO/SDRAM)
Expansion Slots 1 AGP Slot
4 PCI Slots
3 ISA Slots (1 Shared / 3 Full Length)


The Good

Expandability seems to be virtually standard on almost all of the BX boards out today, the 4 PCI, 3 ISA, 1 AGP peripheral card expansion configuration is plenty for average users, and the 3 DIMM slots on-board the P2XBL should be adequate for most user's needs.  The layout of the P2XBL is almost identical to the ASUS P2B, in a somewhat cramped ATX form factor board. 

The P2XBL is configured via the use of a fairly simple Dip-Switch setup to control the clock multiplier, with the Bus Speed auto-configured by the BIOS or manually set in the Setup.  You can choose from a list of Bus speeds ranging from 50 - 133MHz, all of which boot when used with PC100 SDRAM.  If you notice, the Chipset Features Setup of the P2XBL's Award BIOS doesn't list any options to configure any SDRAM Timings...so how are these timings set?  By using the Serial Presence Detect ROM on PC100 SDRAM the P2XBL automatically configures your SDRAM for the best possible balance between stability and performance, it is for this reason that the P2XBL is the only board out of the roundup to date that managed to boot at 133MHz.  p2xbl.jpg (8786 bytes)
Although the ABIT BX6 and the AOpen AX6B both support this feature of SDRAM Auto-Configuration, it seems as if the P2XBL takes matters completely into its own hands, which means for one thing that those of you with regular SDRAM (no SPDROM on-board) will be out of luck when it comes to achieving the best combination of stable/fast memory timings.  It also means that if the P2XBL encounters a communication error between the Chipset and the SDRAM you will suffer in the end, possibly plagued by instability.

The motherboard itself appears to be designed with quality in mind.  The presence of only 3 DIMM slots, like with the ASUS P2B, eliminates the need for any external DRAM Data Buffers, and the placement of the 14 mid-sized capacitors around the CPU Slot Interface and the DIMM slots account for this board's stability during normal operation.  Like all other BX motherboards, in order to keep the intense heat production of the BX Chipset under control, the P2XBL features a decent sized eye-catching orange heatsink on the chipset itself. 

The P2XBL manual is fairly thorough, although still lacks the depth necessary to be placed on the same platform as the ASUS, AOpen, and ABIT manuals.  The documented settings include all clock multipliers ranging from 3.0x - 8.0x, the latter few which are indicated as being Reserved for Future Microprocessors, although it is highly unlikely that we'll ever see a Pentium II - 800 running on a BX board at 100 x 8.0.

Concluding "The Good" section of this review, the price of the DFI P2XBL can't be beat, at $169 the P2XBL even makes the relatively affordable ABIT BX6 appear to be overpriced.  If we have learned anything from the PC Hardware world it is that 9 out of 10 times, you get what you pay for in this industry - leading us to "The Bad" part of this review...

The Bad

First of all, the positioning of the Dip Switch block on the P2XBL couldn't be worse, it is snugly fit between the Pentium II's SEC Slot and a mid-sized capacitor, making a tiny pen or screw driver almost a pre-requisite for configuring this motherboard (unless you have extremely tiny fingers).

Secondly, while the 133MHz setting did boot, the system wasn't stable enough to complete a full run of Winstone, this could be expected due to the use of 8ns SDRAM whose theoretical limit is 125MHz.  Unfortunately, the 112MHz setting was quite erratic as well, leading to the conclusion that the P2XBL's Memory Timing Auto Detect could be improved just a little bit, since all the other motherboards tested that supported the 112MHz bus speed setting had no problem running the Corsair PC100 SDRAM tested at that speed.

Finally, the performance of the P2XBL could be improved just a little bit, it fell behind in all of the Winstone tests, therefore completely dropping it out of the race for the Best BX Board out.


BIOS Settings

DFI P2XBL Chipset Features Setup

Item Recommended Settings
EDO/SDRAM 66/75/83MHz Bus SDRAM 100/133MHz Bus Safe
DRAM Data Integrity Mode: Non-ECC Non-ECC Non-ECC
System BIOS Cacheable: Enabled Enabled Disabled
Video BIOS Cacheable: Enabled Enabled Disabled
Video RAM Cacheable: Disabled Disabled Disabled
8 Bit I/O Recovery Time: 1 4 4
16 Bit I/O Recovery Time: 1 2 2
Memory Hole At 15M-16M: Disabled Disabled Disabled
Passive Release: Enabled Enabled Disabled
Delayed Transaction: Enabled Enabled Disabled
AGP Aperture Size (MB): 64 64 64


Recommended SDRAM

Recommended SDRAM: Corsair PC100 SDRAM
SDRAM Tested: 1 x 64MB Corsair PC100 SDRAM

Manufacturer: Corsair Microsystems
Purchase Web-Site: http://www.nf-ny.com 


The Test

In recent times, choosing a motherboard cannot be completely determined by a Winstone score. Now, many boards come within one Winstone point of each other and therefore the need to benchmark boards against each other falls. Therefore you shouldn't base your decision entirely on the benchmarks you see here, but also on the technical features and advantages of this particular board, seeing as that will probably make the greatest difference in your overall experience.

How I Tested

  • Each benchmark was run a minimum of 2 times and a maximum of 5 times, if the motherboard failed to complete a single test within the 5 allocated test runs the OS/Software was re-installed on a freshly formatted Hard Drive and the BIOS settings were adjusted to prevent the test from failing again.  All such encounters were noted at the exact time of their occurrence.

  • Business Winstone 98 was run at each individually tested clock speed, if reliable scores were achieved with the first two test runs of the suite an average of the two was taken and recorded as the final score at that clock speed.  If the test system displayed erratic behavior while the tests were running or the results were incredibly low/high the tests were re-run up to 5 times and an average of all the test runs was taken and recorded at the final score at that clock speed

  • After each motherboard was tested a complete format of the test hard drive was initiated and the OS/benchmarking software was re-installed afterwards a defragment was initiated using Windows 95's Disk Defragmentation Utility

  • Tests using AGP Video cards were run under Winstone 97 and Winstone 98

  • No foreign drivers were present in the test system other than those required for the system to function to the best of its ability

  • All foreign installation files were moved to a separate partition during the test as to prevent them from effecting the test results

  • All tests were conducted at 800 x 600 x 256 colors


Test Configuration

Processor(s): Pentium II - 300 Retail
Pentium II - 333 OEM
Pentium II - 350 OEM
Pentium II - 400 OEM
RAM: 1 - 64MB Corsair PC100 SDRAM DIMM
Hard Drive(s): Western Digital Caviar AC21600H
Video Card(s): Matrox Millennium II (4MB WRAM - AGP)
Bus Master Drivers: Intel v3.01
Video Drivers: MGA Millennium
Operation System(s): Windows 95 Service Release 2


Ziff Davis Winstone - Windows 95 Performance

Business Winstone 98 Business Winstone 97
Intel Pentium II - 300 (66 x 4.5) --- 64.9
Intel Pentium II - 300 (100 x 3.0) --- 65.9
Intel Pentium II - 350 (100 x 3.5) --- 69.6
Intel Pentium II Deschutes - 333 (66 x 5.0) --- 67.9
Intel Pentium II Deschutes - 350 (100 x 3.5) 23.2 69.4
Intel Pentium II Deschutes - 400 (100 x 4.0) 24.6 73.3
Intel Pentium II Deschutes - 336 (112 x 3.0) Failed Failed
Intel Pentium II Deschutes - 448 (112 x 4.0) Failed Failed
Intel Pentium II Deschutes - 399 (133 x 3.0) Failed Failed


The Final Decision

If your belt is kind of tight, and you simply can't live without a BX board now, then the DFI P2XBL is probably the answer to your prayers.  Otherwise, save up an extra 10 bucks and pick up the ABIT BX6.

Click here to find lowest prices on this product.

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