Thursday, July 27, 2000

The features

Now that we've shone some light on the nature of the i815 chipset, it's time to get down to the brass tacks.

The PT-815TX is expandable via its 4 PCI slots, single AGP port, and AMR (or is it CNR) slot; sorry, no ISA slots to be found here. This selection seems to be a bit narrow, in our opinion... There are also 3 168-DIMM sockets, which can support up to 1536MB of PC100 or PC133 memory according to the manufacturer. Of course, according to Intel, the i815 can only support 512MB of active memory. What are we to make of this? Well, to take a page from Azza's technical support:

By using both the processor, and the memory at a speed of 100MHz, and implementing memory modules of 512MB, it is possible - in theory - to obtain a sum total of 1536MB of memory; granted that 512MB modules are quite rare.

It's true that - also in theory - if both the CPU, and memory are operating at 133MHz, it may only be possible to install 2 modules of PC133 memory as the memory sub-system is very sensitive to the frequency of the memory bus. However, that does not necessarily mean that 3 PC133 modules could not be used if they happen to be of very high quality. In such a case, it may be possible to exceed the recommendation. Also, the majority of Awards BIOS do not automatically reduce the frequency of the memory bus to 100MHz in the presence of 3 PC133 modules, as is suggested by Intel.

It's also worth noting that when both the CPU, and memory bus are operating at 100MHz, that this limitation is not imposed at all.

It is also true, however, that if the memory bus is set to 133MHz, and the CPU installed uses an FSB of 100MHz, that the memory bus will be automatically stepped-down to 100MHz as well.

To terminate, in order to shed further light on the information supplied earlier, let's take a look at the tests performed by Azza themselves as show in the below table:

Configuration of the PT-815TX is accomplished, for the most part, from within the BIOS, as there are few jumpers on the board itself. Among the more important ones, there are jumpers JP2 & JP3 which permit to lock the Vcore voltage to a value between 1.30v, and 2.05v, or to unlock it, and permit it to vary automatically from 1.30v to 3.5v. Azza seems to have put this jumper in place in order to avoid any error that could damage the CPU. By limiting the Vcore to 2.05v, there is little chance of such damage occurring. JP3 itself serves only to raise the Vcore voltage by 0.05v. Finally, a set of DIP switches can be used to force the FSB to 66MHz, 100MHz, or 133MHz, or to allow the frequency to be determined automatically by the system. Adjustment of the operating frequency of the CPU can be made from within the BIOS through the "Frequency/Voltage Control" menu. Once there, a selection of frequencies ranging from 66MHz to 145MHz present themselves. Among the available frequencies are 66Mhz, 67Mhz, 70Mhz, 75Mhz, 80Mhz, 83Mhz,100Mhz, 103Mhz, 105Mhz, 110Mhz, 115Mhz, 124Mhz, 133Mhz, 134Mhz,137Mhz, 140Mhz, and 145Mhz.

Another feature, this one found within the "Chipset Features Setup" BIOS menu, is the option to set the operating frequency of the memory bus to a value 33MHz higher or lower than that of the FSB.

Other particularities

The PT-815TX board also sports a few other features worth mentioning, such as the AIR Bus system described below.

AIR Bus

The AIR Bus is a socket that allows the user to insert a KeyBIOS. By inserting the KeyBIOS, it is possible to reset a BIOS that has been damaged or destroyed by a virus, or to protect your system against unwanted intrusions. This programmable bit of silicon also allows one to keep a secure copy of the information contained within the system BIOS.

Next: The features (continued).