The Intel 440BX chipset has been with us ever since it was introduced in May of 1998.  This is quite unusual for a Slot-1 chipset since the first two chipsets for the Pentium II never lasted more than a few months.  The first Pentium II chipset, the 440FX, lasted only a few months, from the introduction of the Pentium II until August of 1997 when the 440LX chipset made its debut.  The latter managed to stay alive for 7 months before being replaced by the 440BX chipset.  So why is it that the BX chipset has been around for an incredible 24 months and is still being used by motherboard manufacturers?

In order to answer that question you have to go back to the theory that necessity is the mother of invention. 

Intel needed a chipset for the Pentium II and they needed it at the release of the CPU in May and not a few months later.  What they ended up doing was taking the 440FX chipset, otherwise known as the Natoma, which was used on entry-level Pentium Pro motherboards and presented it to motherboard manufacturers as a Pentium II solution as well (because of the fact that the Pentium II used the same bus as the Pentium Pro). 

While the Pentium II was gaining momentum, Intel was working on implementing a "new" graphics bus into their next 440 chipset, which ended up being the 440LX, the world's first AGP enabled chipset. 

The upgrade to the BX came about because Intel felt the need to leave the limiting 66MHz FSB of the Pentium II 333/300/266/233 behind and replace it with a faster 100MHz FSB frequency.  This increase in FSB frequency would not only lower the clock multiplier of future Pentium II CPUs but it primarily offered a higher bandwidth data path from the CPU to the chipset and to the memory.  With the AGP bus taking up to 533MB/s of system bus/memory bandwidth, the 533MB/s of available memory bandwidth on the 66MHz 440LX chipset could potentially become a limiting factor; by increasing the system bus and memory bus operating frequency to 100MHz, the amount of available memory bandwidth also increased to 800MB/s. 

The next step in the evolution of Intel chipsets came with what was then known as the Camino chipset, the successor to the popular BX.  It was originally thought that the Camino chipset, now known as the i820, would offer everything the BX chipset had to offer while adding 133MHz FSB support as well as Ultra DMA 66 support.  As more information was released, it quickly became known that the i820 would support a brand new type of memory, RDRAM, but at the same time, the chipset would be able to work alongside SDRAM. 

While all of these rumors ended up coming true in one sense or another – i820 did add 133MHz FSB/Ultra DMA 66 support and it did support SDRAM in addition to RDRAM (however only if a Memory Translator Hub was implemented on the motherboard) – the fact of the matter was that the i820 as a platform was not affordable enough (thanks to the high price associated with RDRAM), didn't offer a large enough performance improvement over the 440BX, and its even poorer performance and possibly instability when used in conjunction with SDRAM and an MTH made this chipset a highly undesirable solution, even by motherboard manufacturers. 

This put motherboard manufacturers in an interesting situation.  Intel was obviously pressuring them to promote and sell as many i820 motherboards as possible yet they couldn't since there wasn't a great enough demand for them.  VIA began offering their Apollo Pro 133A chipset to motherboard manufacturers that needed 133MHz FSB support without having to move to i820.  Unfortunately, in the usual manner of VIA chipsets, the Apollo Pro 133A's overall performance was not the best, and in a head-to-head comparison, at the 100MHz FSB the Intel 440BX chipset would actually pull out ahead.

The only real advantage VIA's 133A offered over the 440BX was that it officially supported the 133MHz FSB frequency, and with the 1/2 AGP multiplier, that would allow the AGP bus to operate within spec when the FSB is set to 133MHz (133/2 = 66MHz = AGP spec clock speed). 

Even the first BX motherboards ever released featured unofficial support for the 133MHz FSB setting, but there was a lack of memory that could run at that frequency (as memory was just starting to ship as PC100 compatible) as well as a lack of AGP video cards that were capable of running at 89MHz, which is what the AGP bus would operate at when the FSB was raised to 133MHz (133 * 2/3 = 89MHz = 35% over 66MHz spec). 

BX at 133MHz

As we mentioned in our RDRAM Performance article, the BX chipset is now capable of running, albeit unofficially, at the 133MHz FSB frequency.  What has changed since May 1998 that allows for a BX motherboard to run at 133MHz?

For one thing, motherboard manufacturers have been tweaking their designs quite a bit over the past two years.  The BX motherboard platform in general is at the point where you shouldn't have to worry too much about variations in performance or stability when going from one motherboard to the next.  This perfection of the motherboard design, especially from the companies that have had quite a few BX boards (i.e. ASUS, ABIT…) has made their reliability at higher FSB frequencies much more of a reality and less of a dream.

Secondly, the PC133 memory standard has been completed and implemented by VIA as well as refined by Intel.  There is finally memory available that was designed with a 133MHz operating frequency in mind, and not too long ago Micron began shipping their –7E parts, which are officially rated at 133MHz CAS2, which provides for an additional 5 – 10% performance improvement over 133MHz CAS3. 

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Finally, video card manufacturers have been designing their video cards to operate at a greater range of frequencies that remain outside of the 66MHz AGP specification. 

A combination of all three of these factors has made it possible to run BX motherboards at the 133MHz frequency, even without the presence of a 1/2 AGP clock divider (there would have to be a revision of the BX North Bridge in order to add support for that divider).  Now, not all BX motherboards are capable of running at the 133MHz FSB, but there is definitely a high chance of it working on the latest BX motherboards, especially those produced by such companies as ABIT, ASUS, AOpen, and MSI, to name a few. 

Ultra DMA 66 on a BX?

It doesn't make sense to buy a BX motherboard now with hopes of it remaining capable of running the latest processors in a few months (Willamette will use a completely different bus), but one thing a lot of potential BX motherboards owners were worried about was not having Ultra DMA 66 support on their BX motherboards.

As we proved in our Ultra DMA 33 vs. Ultra DMA 66 comparison, the Ultra DMA 66 specification does not provide any tangible performance benefits for today's hard drives but that is quickly changing.  The IBM Deskstar 75GXP is supposed to be able to provide performance that is limited by the Ultra DMA 33 specification, which could cause problems for BX motherboard users since their boards would be limiting their disk performance.

Last year, when it became clear that the BX chipset would be around for at least a little while longer while Intel readied the i820 chipset, motherboard manufacturers began adding external Ultra DMA 66 controllers to their motherboards.  At that time, there wasn't really a need for Ultra DMA 66 support since no hard drives could burst at above 33MB/s, but quite a few users went after the motherboards simply because they supported Ultra DMA 66. 

There are a few options for users when it comes to having Ultra DMA 66 support on a BX motherboard.  Currently Promise, CMD and High Point manufacture controllers that are being used on BX motherboards in order to add Ultra DMA 66 support.  Moreover, if your motherboard doesn't feature either one of those on-board controllers, you can always purchase an add-on card that features either one of the controllers. 

High Point HPT366

Used on: ABIT BE6-II & Soyo SY-6BA+IV

Promise PDC20262

Used on: Gigabyte GA-6BX7+ & Microstar BXMaster

CMD 648

Used on: ASUS CUBX

AGP 2X vs. AGP 4X

Another one of the paper advantages the i820 and Apollo Pro 133A chipsets hold over the old 440BX is their support for AGP 4X transfer modes which are theoretically twice as fast as the AGP 2X transfer rates supported by the BX chipset. 

The 32-bit wide AGP bus, when operating in 2X mode allows for a peak transfer rate of 533MB/s.  The same AGP bus, when operating in 4X mode allows for a peak transfer rate of 1.06GB/s.  Going by those two numbers alone, you definitely see where AGP 4X can hold a performance improvement over AGP 2X, but if you take into account that the amount of available memory bandwidth on your graphics card is going to be between 3 – 5GB/s (2.7GB/s for GeForce and 5.3GB/s for GeForce 2), all of the sudden this 1.06GB/s of memory bandwidth offered by AGP 4X isn't all that great. 

The performance hit you get when going from local memory on your graphics card to system memory via the AGP bus is so great that the difference between the AGP 4X transfer rates and AGP 2X transfer rates remains of very little significance. 

Another thing to take into account is that, since the BX chipset only supports an AGP to FSB ratio of 2/3 or 1/1, at 133MHz FSB the AGP bus will be running at 89MHz which is a full 33% over the 66MHz specification.  This also translates into a higher transfer rate across the AGP bus since the operating frequency of the bus is higher.  More specifically, at 89MHz, you get something along the lines of an AGP 3X transfer rate although a bit slower than what that would actually be (since 100MHz AGP would theoretically be equal to AGP 3X).  The actual peak transfer rate across the AGP bus then becomes around 712MB/s which is a 34% increase over the 533MB/s of AGP 2X. 

In order to prove that the difference between AGP 4X and AGP 2X is negligible, we naturally ran a set of benchmarks comparing the two.  In order to eliminate all potential bottlenecks and truly compare AGP 4X and AGP 2X, we ran the benchmarks on an i820 platform with a GeForce 2 GTS.  For comparison's sake, we've included AGP 1X scores as well.

As you can see, in a normal gaming situation, there is very little difference between AGP 4X and AGP 2X.

Even in a memory intensive situation such as Quaver, the difference is not that great. Although in this particular case, the GeForce's S3TC support as well as enhanced texture management routines that are a part of the 5.22 Detonator drivers increase the efficiency of the use of local graphics memory thus minimizing the need for AGP texturing.

In a high end test which is represented by SPECviewperf, the performance difference between AGP 2X and AGP 4X is negligable but there is definitely a huge difference present between AGP 1X and the latter two transfer modes.

The Candidates

We rounded up a total of seven BX motherboards for this roundup: the ABIT BF6, ABIT BE6-II, AOpen AX6BXC Pro Gold, ASUS CUBX, Gigabyte GA-6BX7+, Microstar BXMaster, and the Soyo SY-6BA+IV.

The first thing we noticed after running through all of the benchmarks and stability tests was that, overall, each one of the seven boards performed just about equally in terms of stability when running at 133MHz. 

No board crashed more than three times during a 24-hour looped run of Content Creation Winstone 2000.  This is compared to the 6+ times that most average Apollo Pro 133A and VIA KX133 motherboards crash during the same 24-hour period.  The BX platform is definitely very refined, and even when overclocked, provided that you have properly selected your components (PCI cards don't really matter since you can run your PCI bus at 133MHz / 4 which keeps them in spec at 33MHz), your BX133 platform should be just as stable as any other 133MHz platform out there. 

The highest we could push any of these boards reliably was around the 155MHz FSB.  The Soyo SY-6BA+IV was one of the only boards to run our 733MHz test chip at 155MHz x 5.5 reliably, even while running 3D games and applications.  But at 155MHz x 5.5, there was a noticeable drop in stability when compared to the SY-6BA+IV at the 133MHz setting.  We could've probably pushed the board even higher, but it lacked the FSB settings to go any higher.  Before you start asking, our ABIT BF6 was only able to get to around 150MHz before our benchmarks would no longer run reliably, so the 1MHz FSB increments above 150MHz weren't of much use.  We tested this using Micron –7E SDRAM, which is rated at 133MHz CAS2 and is the only currently available PC133 SDRAM capable of running at 133MHz CAS2. 

Another issue we encountered was that on the ASUS CUBX, the CMD controller that provides for Ultra DMA 66 functionality required that we manually enable the Ultra DMA 66 setting, in spite of the fact that we were using Ultra DMA 66 drives and cables. 

Regarding all of the boards that feature external Ultra DMA 66 controllers, if the drivers for those controllers were not installed properly or at all from the start, we noticed very erratic behavior under Windows often resulting in random lockups and failures to boot Windows properly, so make sure you get those drivers installed. 

The HighPoint controller on the ABIT and Soyo motherboards was the only Ultra DMA 66 controller to come up as two devices under the SCSI devices section of Windows' Device Manager.  At the same time, the CMD controller on the ASUS CUBX was the only controller to come up properly as an IDE controller.  Those are just some of the odd quirks about working with these boards.

ABIT BF6 - Click Here for the AnandTech Review

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The ABIT BF6 is a fairly average BX motherboard.  It does not feature any Ultra DMA 66 controllers or additional USB ports, aside from the 2 provided by the Intel PIIX4e South Bridge. 

The board does feature 6 PCI slots, but without an external PCI arbiter chip, only five of them can support bus master devices, the 6^th PCI slot remains a slave capable of being populated by cards that don't require a master slot.  Unfortunately, the number of devices that can operate in a slave slot are limited and include some PCI graphics accelerators, a Voodoo2, and some Ethernet adapters.  So for most purposes, the BF6 is really only a 5 PCI slot motherboard. 

Out of the 6 PCI slots on the BF6, 5 are capable of accepting full-length cards, which is very useful to know if you're planning to get a PCI Voodoo5.  The single ISA slot present on the board can't accept a full-length card, but as long as you're not planning to re-use your extremely old ISA peripherals, you should be fine. 

The AGP slot on the BF6 can share an IRQ with either the first or the second PCI slot depending on which one is populated (assuming only one is), the third and sixth PCI slots share an IRQ and the fourth and fifth PCI slots share an IRQ with the USB controller.  This is a fairly standard IRQ sharing map for a BX motherboard with 6 PCI slots. 

What makes the BF6 stand out from the rest of the crowd is ABIT's patented SoftMenu III Jumperless CPU Setup & Configuration utility that is integrated into the board's Award 6.00PG BIOS.  SoftMenu III provides for a total of 120 FSB speed settings, more specifically standard 66 / 75 / 83 settings plus speeds from 84 - 200 in 1MHz increments.  There is still support for adjusting the PCI ratio (1/2, 1/3, or 1/4 of the FSB speed), AGP ratio (2/3 or 1/1 of the FSB speed), and CPU core voltage (default +/- 0.3V). SoftMenu III also offers the ability to adjust the I/O voltage of the PCI / AGP bus and SDRAM to 3.2 - 3.9V in 0.1 V steps (default is 3.3V), as well as some options for L2 cache latency, all in an effort maximize overclocking potential. The defaults for all these settings are clearly labeled, so causing serious damage will take a bit of work.

In addition to the SoftMenu III jumperless setup, the BF6 features a set of 10 dip switches that can control the otherwise jumperless features on-board.  This is mainly for OEMs and system integrators and doesn't really apply to most hardware enthusiasts. 

The BF6 managed to get quite a few BIOS updates from ABIT that supposedly improved stability when running at 133MHz FSB.  We tried our BF6 with an older BIOS revision as well as the newer RV revision, which claimed to "improve the 133MHz option in SoftMenu."  While the BF6 would lock up under 3D games and applications using older BIOS revisions, under the RV revision, the system was noticeably more reliable and it wouldn't lock up under 3D games and applications.  This BIOS is available on ABIT's download site.

ABIT BE6-II - Click Here for the AnandTech Review

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The BE6-II is essentially the same as the BF6 with one notable exception – the BE6-II features an integrated HighPoint HPT366 Ultra DMA 66 controller, thus adding Ultra DMA 66 support to the motherboard. 

Because of the presence of the HPT366 controller on board, the BE6-II loses one PCI slot from the 6 that the BF6 has, since the HPT366 acts as a PCI device.  The HPT366 and the first four PCI slots are bus master capable, thus leaving the fifth PCI slot as a slave slot, much like the 6^th PCI slot on the BF6. 

Unfortunately, the number of devices that can operate in a slave slot are limited and include some PCI graphics accelerators, a Voodoo2, and some Ethernet adapters.  So for most purposes, the BE6-II is really only a 4 PCI slot motherboard. 

Just like the BF6, the BE6-II features 5 full length PCI slots while the single ISA slot is not capable of accepting a full length card. 

The on-board HPT366 doesn't change the way the BE6-II shares its IRQs at all.  The AGP slot can still share an IRQ with either the first or the second PCI slot, the fourth and fifth slots still share an IRQ with the USB controller, but instead of the third slot sharing an IRQ with the sixth PCI slot (since there is no 6^th PCI slot), the third slot shares an IRQ with the on-board HPT366 controller. 

The HPT366 has been known to have compatibility problems with certain devices, including CDROMs and even some hard drives.  Your best bet is to search around the net to see if anyone has had any troubles with their BE6-IIs and the particular devices you plan on having on the HPT366 channels.  One benefit of having this controller on-board is that you still have the two Ultra DMA 33 channels courtesy of Intel's PIIX4e South Bridge, which can be used for all non-Ultra DMA 66 devices. 

Like the BF6, ABIT's patented SoftMenu III Jumperless CPU Setup & Configuration makes the BE6-II stand out from the crowd.  The utility that is integrated into the board's Award 6.00PG BIOS provides for a total of 120 FSB speed settings, more specifically standard 66 / 75 / 83 settings plus speeds from 84 - 200 in 1MHz increments.  There is still support for adjusting the PCI ratio (1/2, 1/3, or 1/4 of the FSB speed), AGP ratio (2/3 or 1/1 of the FSB speed), and CPU core voltage (default +/- 0.3V). SoftMenu III also offers the ability to adjust the I/O voltage of the PCI / AGP bus and SDRAM to 3.2 - 3.9V in 0.1 V steps (default is 3.3V) as well as some options for L2 cache latency, all in an effort maximize overclocking potential. The defaults for all these settings are clearly labeled, so causing serious damage will take a bit of work.

In addition to the SoftMenu III jumperless setup, the BE6-II features a set of 10 dip switches that can control the otherwise jumperless features on-board.  This is mainly for OEMs and system integrators and doesn't really apply to most hardware enthusiasts. 

Once again, like the BF6, the BE6-II managed to get quite a few BIOS updates from ABIT (it actually uses the same BIOS) that supposedly improved stability when running at 133MHz FSB.  We tried our BE6-II with an older BIOS revision as well as the newer RV revision, which claimed to "improve the 133MHz option in SoftMenu."  In our tests it definitely did: while the BE6-II would lock up under 3D games and applications using older BIOS revisions, under the RV revision the system was noticeably more reliable.  This BIOS is available on ABIT's download site.

AOpen AX6BC Pro Gold - Click Here for the AnandTech Review

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When we reviewed it back in July of 1999, the AX6BC Pro Gold left a lasting impression on us.  The impression was great enough that it won our Editor's Choice award for best Slot-1 BX motherboard at the time.  Now, using the 133MHz FSB on the board, it's still just as impressive.

The board remains unchanged from when it was released in 1999; it still features no Ultra DMA 66 controllers and no extra USB ports.  The 'Gold' suffix in its name comes from the gold plated heatsink that is present on the 443BX North Bridge, which doesn't do all that much other than to attract attention to the motherboard itself. 

The AX6BC Pro features 5 PCI slots, all of which are bus master PCI slots.  Four of the five slots are capable of accepting full length cards while the fifth slot is blocked by a 3-pin fan connector. 

The board shares IRQs just like every other board, the first and second PCI slots are shared with the AGP slot.  The fourth and fifth PCI slots share an IRQ with the on-board USB controller, and finally, the third PCI slot is the ideal one to install your PCI peripherals in since it does not share an IRQ with any other slots. 

The AX6BC Pro Gold features a fully jumperless CPU configuration utility present in the BIOS.  While it is definitely not as flexible as the ABIT boards in terms of the number of options present in the BIOS setup, it is decent in that it provides you with all of the options you need to get up and running, including FSB and core voltage tweaking.

ASUS CUBX

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The CUBX is ASUS' latest BX motherboard and is definitely worth the wait.  The board is one of two boards present in this roundup that features a Socket-370 interface instead of the usual Slot-1.  This doesn't give it any advantages over the Slot-1 counterparts except for the fact that you can use a Celeron or a Pentium III on the CUBX without spending another $15 on a Socket-370 to Slot-1 adapter card.  The only real downside to the Socket-370-only interface on the CUBX is that you can't use your older Pentium II/III on it, and the area around the CPU socket itself is slightly crowded, which can lead to some of the larger heatsink/fan combos being difficult to install or not fitting at all. 

The CUBX comes with an on-board CMD 648 Ultra DMA 66 controller that provides the board with two Ultra DMA 66 channels in addition to the two Ultra DMA 33 channels

In addition to having on-board Ultra DMA 66 the CUBX also features an additional 2 USB ports courtesy of the Alcor Micro controller present at the lower left corner of the motherboard.  This chip acts as a USB hub so you don't need any drivers for the chip, it is simply detected as a USB hub by Windows. 

For most end users, having more than 2 USB ports doesn't make a lot of sense other than the fact that it saves you from going out and buying a USB hub if you have more than 2 devices.  But for OEMs such as Hewlett Packard that do happen to use ASUS motherboards in some of their systems, the extra USB headers on-board can be used to place USB connectors at the front of their cases.  The CUBX is perfect for this since it not only features an extra 2 USB ports, but it also features a third header which is shared with one of the rear USB ports, allowing you to route it to the front of your case.  It wouldn't be too hard to modify your case so that the USB slot cutout ASUS supplies with the board can be used to provide you with USB ports on the front of your computer.

The CUBX features 6 PCI slots, but because the PIIX4e South Bridge only supports 5 PCI bus master devices, the sixth slot is a slave slot.  At the same time, the fifth slot is also a slave since the CMD controller acts as a bus master PCI device, essentially leaving the CUBX with four PCI slots that you can populate with any PCI devices.  The only types of cards that can work in a slave PCI slot are some PCI video cards, the Voodoo2 (since it doesn't take an IRQ) and some network cards, so for most situations, those last two PCI slots are useless. 

The CUBX's IRQ sharing scheme is a little different than the rest of the boards since it has the 6 PCI slots and the on-board CMD controller.  Again, the AGP slot can share an IRQ with either the first or the second PCI slots, the third and sixth PCI slots share an IRQ as do the fourth and fifth which also share an IRQ with the on-board USB controller.  The on-board CMD controller shares an IRQ with the second slot. 

One gripe we had with the board was the placement of the floppy connector between the first two PCI slots, but other than that the layout was relatively trouble free.  Since the connector was placed between those two slots it did not interfere with the installation of a full length PCI card leaving a total of 4 of the six slots capable of accepting full length cards. 

The CUBX is outfitted with ASUS' own JumperFree setup that allows for the manual selection of FSB and voltage settings for the CPU.  One of the most useful features of the JumperFree setup is that it will resort to a fail-safe setting of 66MHz x 4.0 for Pentium III Coppermine processors and 66MHz x 2.0 for all other CPUs and automatically take you to the Advanced settings menu of the BIOS and allow you to select your CPU frequency provided that the board doesn't boot properly because of an incorrectly configured CPU (or if you overclock it too far).  Just like the BF6/BE6-II, the CUBX features a set of 10 dip switches that can override the JumperFree setting, mainly for OEMs and system integrators that don't want their users playing around with the settings unless they know what they're doing.

The board also features the ability to increase the chipset I/O voltage which ships by default at 3.45v (which is already up from the 3.3v standard voltage).  You can choose from 3.45v or 3.60v as the two possible settings for the I/O voltage. 

Update 06/19/2000:

Gigabyte just informed us that the GA-6BX7+ features a custom PAL (programmable array logic) chip that allows the 6BX7+ to support two more PCI master slots. This means that all of the PCI slots on the 6BX7+ are master slots.

Gigabyte GA-6BX7+

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Motherboard Specifications
CPU Interface	Socket-370
Chipset	Intel 440BX
L2 Cache	N/A (on-chip)
Form Factor	ATX
Bus Speeds	66 / 100 / 112 / 124 / 133 / 142 / 152
Voltages Supported	Auto Detect Adjustable to Vcore + 10 / 20 / 30 / 40 / 50%
Memory Slots	4 168-pin DIMM Slots
Expansion Slots	0 AMR Slots 1 AGP Slot 6 PCI Slots (4 Full Length) 1 ISA Slots (1 Shared / 0 Full Length)
BIOS	Award 4.51PG

 

The GA-6BX7+ is definitely a unique board, not because of its features but rather because of its blue colored PCB.  The board is the second and final Socket-370 unit we tested in the roundup and also happens to be the first of two boards present in this roundup that feature the Promise 20262 Ultra DMA 66 controller. 

The Promise controller provides the board with two Ultra DMA 66 channels and was seemingly less problematic than the HPT366 controller present on the ABIT and Soyo boards. 

In addition to the Promise controller the Gigabyte board features an external Winbond chip that adds support for 2 more USB ports. 

The 6BX7+ features 6 PCI slots, but because the PIIX4e South Bridge only supports 5 PCI bus master devices the sixth slot is a slave slot.  At the same time the fifth slot is also a slave since the Promise controller acts as a bus master PCI device, essentially leaving the 6BX7+ with four PCI slots that you can populate with any PCI devices.  The only types of cards that can work in a slave PCI slot are some PCI video cards, the Voodoo2 (since it doesn't take an IRQ) and some network cards so for most situations those last two PCI slots are useless. 

The 6BX7+'s IRQ sharing scheme is much like that of the CUBX.  The AGP slot can share an IRQ with either the first or the second PCI slots, the third and sixth PCI slots share an IRQ as do the fourth and fifth which also share an IRQ with the on-board USB controller.  The on-board Promise controller shares an IRQ with the third  slot. 

The biggest downside to this motherboard is the fact that it has no jumperless CPU setup.  Everything is controlled by a set of 8 dip switches on the motherboard which is fine for OEMs and system integrators but not the best option for end users and enthusiasts.  Also, the voltage settings provided by Gigabyte aren't the greatest variety of settings.  Gigabyte calls the voltage selection their "Magic Booster" (don't ask) and it allows you to select a voltage that is 10%, 20%, 30%, 40% or 50% higher than the default core voltage.  This means for a 1.65v CPU the lowest voltage increase you can get is up to 1.81v which is a bit excessive if you just need a little boost in core voltage.  Definitely not the choice for overclockers.

The truly unique feature of the 6BX7+ is Gigabyte's Dual BIOS support which allows for a backup of the BIOS to be restored if there is an error in flashing. 

Microstar BXMaster - Click Here for the AnandTech Review

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Motherboard Specifications
CPU Interface	Slot-1
Chipset	Intel 440BX Promise 20262 UDMA 66 Controller
L2 Cache	N/A (on-chip)
Form Factor	ATX
Bus Speeds	66 / 75 / 78 / 81 / 83 / 90 / 95 100 / 105 / 110 / 112 / 115 / 117 / 120 / 122 / 124 126 / 133 / 135 / 138 / 140 / 142 / 144 / 150 / 155
Voltages Supported	Auto Detect Adjustable to 1.3V - 3.5V
Memory Slots	4 168-pin DIMM Slots
Expansion Slots	0 AMR Slots 1 AGP Slot 6 PCI Slots (5 Full Length) 1 ISA Slot (1 shared / 1 full length)
BIOS	Award 4.51PG

 

The Microstar BXMaster is also a holder of the AnandTech Editor's Choice award because of its incredible balance of features and performance. 

Unlike other boards with 6 PCI slots, the BXMaster features a PCI arbiter chip that allows all 6 slots to support bus master devices.  This means that all six slots are usable by any PCI devices. 

The BXMaster also features the Promise 20262 controller that is also found on the Gigabyte GA-6BX7+.  This provides the board with the two Ultra DMA 66 channels that it features in addition to the Ultra DMA 33 channels provided by the Intel PIIX4e South Bridge.  As we mentioned before, we have generally found the Promise controller to have fewer compatibility problems than the High Point controller that is found on the ABIT and Soyo boards. 

It should be noted that the Gigabyte board detects drives much faster than the Microstar BXMaster in spite of the fact that both boards use the same Promise controller. 

The IRQ sharing scheme on the BXMaster is identical to that of the GA-6BX7+. The AGP slot can share an IRQ with either the first or the second PCI slots, the third and sixth PCI slots share an IRQ as do the fourth and fifth which also share an IRQ with the on-board USB controller.  The on-board Promise controller shares an IRQ with the fourth slot. 

The BXMaster still uses the Award 4.51PG BIOS but it features MSI's CPU Plug & Play III Jumperless CPU Configuration Utility.  FSB options include 66 / 75 / 78 / 81 / 83 / 90 / 95 / 100 / 105 / 110 / 112 / 115 / 117 / 120 / 122 / 124 / 126 / 133 / 135 / 138 / 140 / 142 / 144 / 150 / 155, which puts it ahead of virtually everything on the market, surpassed primarily by the ABIT BF6 and BE6-II with their SoftMenu III support. The PCI speed is reported next to the FSB setting, which should help you keep things as close to the 33 MHz PCI spec as possible. PCI ratios of 1:4, 1:3, and 1:2 are automatically set based on FSB speed

Vcore settings range from 1.30 - 2.10V, in 0.05V increments and then from 2.1V to 3.5V in 0.1V steps. Only a limited range of voltages is displayed based on the CPU used - for example, our testbed Pentium III 550E had a default voltage of 1.6V and could be set to anything between 1.30V and 2.00V. An additional feature the MSI has implemented is support for chipset voltage, which ranges from 3.3V to 3.6V in 0.1V steps.

Soyo SY-6BA+IV - Click Here for the AnandTech Review

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Motherboard Specifications
CPU Interface	Slot-1
Chipset	Intel 440BX HighPoint HPT366 UDMA 66 Controller
L2 Cache	N/A (on-chip)
Form Factor	ATX
Bus Speeds	66 / 75 / 81 / 83 / 90 / 95 100 / 105 / 110 / 112 / 113 / 115 117 / 118 / 120 / 122 / 124 / 126 133 / 135 / 137 / 138 / 140 / 142 144 / 150 / 155MHz
Voltages Supported	Auto Detect (may be increased by 2.5%, 5%, 7.5%, and 10%)
Memory Slots	4 168-pin DIMM Slots
Expansion Slots	0 AMR Slots 1 AGP Slot 5 PCI Slots (4 Full Length) 1 ISA Slots (1 Shared / 0 Full Length)
BIOS	Award 4.51PG

 

The Soyo 6BA+IV closely resembles the ABIT BE6-II in that it features 5 PCI slots, and an on-board HighPoint Ultra DMA 66 controller (HPT366). 

The HPT366 and the first four PCI slots are bus master capable, thus leaving the fifth PCI slot as a slave slot.

Unfortunately, the number of devices that can operate in a slave slot are limited and include some PCI graphics accelerators, a Voodoo2, and some Ethernet adapters.  So for most purposes, the 6BA+IV is really only a 4 PCI slot motherboard. 

IRQ sharing on the 6BA+IV is like the rest of the boards reviewed here.  The AGP slot can share an IRQ with either the first or the second PCI slots, the third and sixth PCI slots share an IRQ as do the fourth and fifth which also share an IRQ with the on-board USB controller.  The on-board HighPoint controller shares an IRQ with the second slot. 

The SY-6BA+IV features the "Soyo Combo Setup" where most important settings are found. Control over FSB, CPU ratio, AGP ratio, core voltage, and hardware monitoring all found in this section. Notably, Soyo has added an option for cache latency control to keep up with ABIT's plethora of tweaking options. The default is reported, but any setting from 1 to 15 can be selected. FSB settings of 66 / 75 / 81 / 83 / 90 / 95 / 100 / 105 / 110 / 112 / 113 / 115 / 117 / 118 / 120 / 122 / 124 / 126 / 133 / 135 / 137 / 138 / 140 / 142 / 144 / 150 / 155MHz are all available.

To help with every last bit of overclocking, core voltage can be increased by 2.5%, 5%, 7.5%, and 10%

The Test

Test Configuration
Processor(s):	Intel Pentium III 733
RAM:	1 x 128MB Corsair PC133 SDRAM (Micron -7E Chips)
Hard Drive(s):	Western Digital 153BA Ultra ATA 66 7200 RPM
Bus Master Drivers:	Windows 98SE Default
Video Card(s):	NVIDIA GeForce 256 SDR
Video Drivers:	NVIDIA Detonator 5.22
Operation System(s):	Windows 98 SE
Motherboard Revisions:	ABIT BF6 Revision 1.0 ABIT BE6-II Revision 1.0 AOpen AX6BXC Pro Gold Revision 1.0 ASUS CUBX Revision 1.02 Gigabyte GA-6BX7+ Revision 1.1 Microstar BXMaster Revision 1.0 Soyo SY-6BA+IV Revision 1.0

Most of the boards here performed within 1% of each other, while you could definitely notice the difference between the Soyo SY-6BA+IV, ABIT BF6 and AX6BC Pro Gold and the rest of the boards.

Once again the BF6 pulls up the rear while the Microstar BXMaster and the ASUS CUBX pull ahead of the other competitors.

Under Quake III Arena the boards performed within 2 fps of each other, this helps to prove the point that the BX platform has risen to the point where there is relatively no performance difference between two boards based on the chipset.

Final Words

Overall there are two motherboards that definitely stand out among the seven in this roundup, the ASUS CUBX and the Microstar BXMaster.    The CUBX is definitely a very well made Socket-370 motherboard.  Its combination of an on-board Ultra DMA 66 controller and an additional USB hub works alongside the board's JumperFree setup to make the CUBX very well rounded.  If you have a Socket-370 CPU and are looking for a BX motherboard that can run at 133MHz then the CUBX is definitely the board you want to pick.

On the Slot-1 end of things, the Microstar BXMaster continues to be our favorite since Microstar managed to get around the 5 bus master PCI slot limitation of the Intel PIIX4e South Bridge by using their custom made PCI arbiter chip.  The six usable PCI slots on the BXMaster combined with the Promise Ultra DMA 66 controller and the greater than average performance make the BXMaster our second pick for best overall BX board.  If you want the flexibility of a Slot-1 interface, then the BXMaster is the board you'll want to get. 

In the end, it seems quite ironic that seven months after the official launch of the i820 chipset we're not rounding up the best 820 boards rather we're concentrating on the top seven boards based on a chipset that preceded the 820's release by over a year and a half.  It seems like it takes quite a bit to replace a really good product, even if it's being replaced by the same manufacturer.