ABIT BP6 i440BX Dual Socket-370 ATXby Anand Lal Shimpi on July 20, 1999 12:24 AM EST
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As you're probably already aware of, there is a manipulation possible to allow for a Slot-1 (SEPP) Celeron or a Socket-370 (PPGA) to operate in dual processor mode. What ABIT did was essentially make this modification to the motherboard itself, so the sockets provide the proper current manipulation allowing for the current generation of Socket-370 Celerons to work in the BP6 in dual processor mode. A simple idea, and ABIT was the first to implement and ship it. However making a dual processor board isn't as easy as simply adding another socket.
The number of capacitors around the SC242 Slot-1 connector on the BX6R2, surprisingly enough, is exactly 1/2 the count found around the two Socket-370 connectors on the BP6. Use that knowledge for what it's worth, but for a dual processor motherboard, the BP6's PCB seemed very bare.
Although ABIT recommends that you install two similar CPUs (i.e. same clock, same stepping) if using the BP6 in dual processor mode, you can use two different CPUs and the system will function. The BP6 features ABIT's well known SoftMenu jumperless CPU configuration utility with a bit of a twist for the nature of this board. The BH6/BX6R2 boards brought voltage tweaking to the Pentium II/Celeron platform, and the BP6 takes that one step further by allowing you to independently set the core voltage of each of the two CPUs installed (provided that two CPUs are installed, otherwise the voltage for a single CPU is equally as configurable). This is extremely helpful if one CPU requires a little more voltage to overclock than the other, this way you won't have to sacrifice the benefits of overclocking for dual processor operation. The best way to test the ideal voltages for each one of your installed CPUs individually is to install one at a time and run stability tests on them individually at various core voltage settings, then use the appropriate settings for each processor when operating in dual processor mode.
The BP6's SoftMenu II takes advantage of the new clock generator on the BP6 by providing support, albeit unofficially, for a total of 27 FSB settings. ABIT's FSB support is much more intelligent than that of many competing manufacturers as 23 of the 27 settings are FSB settings between 66MHz and 100MHz, the overclocking sweet spot for Celeron processors. In addition to the standard 66/75/83/100/124/133MHz FSB settings, the BP6 supports the 72/78/80MHz settings, as well as FSB settings ranging from 82MHz - 100MHz in 1MHz increments. For those users that are keen on getting the most performance from their system, the BP6 offers the right set of FSB settings and it is the only motherboard thus far to actually support FSB settings that are reasonable for overclocking. Honestly now, how many users are happily running at a 153MHz FSB and still use their computers for more than showing off the 153MHz FSB? The 124/133MHz FSB settings are present for the users that may want to give them a try, however with a 66MHz, clock locked, Celeron, it is highly unlikely that you'll ever run into a situation where the 124MHz FSB would be a viable option. The board also supports the 1/3 PCI clock divider with all > 90MHz FSB settings and the 1/4 PCI clock divider with all > 100MHz FSB settings to keep the PCI frequency as close to the specified 33MHz setting as possible, for those with extremely frequency sensitive PCI peripherals.
The AGP clock is also derived from the FSB frequency, and the BP6's SoftMenu II does offer the ability to select from a 1:1 or a 2:3 FSB ratio for the derivation of the AGP frequency, keeping the clock as close to the rated 66MHz frequency as possible. Complaining about ABIT not including any other AGP ratios is quite futile as the motherboard has nothing to do with the AGP frequency, which is actually stored in the chipset itself and only selected through the motherboard, leaving the 1:1 and 2:3 ratios as the only two options with the BX chipset. It looks like we'll have to wait for Intel's 810 (Camino) or VIA's Apollo Pro Plus 133 chipset before we can see any other AGP clock ratios.
As briefly mentioned above, you can install two different CPUs in the BP6 and still have it function properly, however there may be a loss in stability. In the event that you are running at two separate CPU speeds, each processor retains its individual clock, however the frequency of the processor in the first socket is the one that is reported to the BIOS since the BIOS does not perform a check to make sure that both processors. This does not mean that both processors are running at one speed, the only clock shared by the two is the FSB frequency as they share the same bus (GTL+). Both processors retain their individual frequencies but because they share the same FSB, they cannot be overclocked independently, so if you overclock one processor using a faster FSB frequency, you effectively overclock the other processor as well.
The BP6 is guaranteed to support Intel Celeron processors up to 533MHz in speed provided that they are using the 100MHz FSB, other than that, ABIT offers no guarantee. So the question that is often asked as to whether or not a Socket-370 Pentium III processor will be able to run in single or dual processor mode on the BP6 is essentially up to Intel to decide. Provided that the Socket-370 Pentium III, upon its release, is essentially what the name indicates it should be, a Pentium III in a Socket-370 pin compatible package there should be no reason why it wouldn't work on a BP6. In the case of single processor operation all that should be required is a BIOS update, as the BX chipset provides supports for L2 cache sizes of 0KB (1st generation Celerons), 128KB (Celeron), and 512KB (Pentium II/III). It is highly unlikely that the Socket-370 Pentium III will be able to function in dual processor mode on the BP6. Since the Socket-370 Pentium III would be a new design, and since Intel is planning a different socket for their multiprocessor capable PPGA Pentium IIIs it would make very little sense for Intel to produce a Socket-370 Pentium III that would work perfectly fine in a dual Socket-370 board such as the BP6. Upon its release there may be a method of enabling multiprocessor operation, however the chances are very low that you'd be able to buy two Socket-370 Pentium IIIs upon their release and toss them in your BP6 without any problems.