Thursday, March 02, 2000

Introduction

It's been sometime since motherboards based upon the Intel 820 (Camino) chipset first appeared on the market. While I've received several test units over that time, I was unable to put them through the hoops due to my lack of Rambus memory. As you can guess, the DFI PC64 - as with many similar boards - itself requires Rambus memory. This memory standard, incompatible as it is with conventional PC100 & PC133 memory, is quite expensive. In fact, a 128MB PC800 module will typically sell for about $550us

With that in mind, you can understand the difficulties that are faced in reviewing such boards. Thus, the DFI PC64 will be the first i820 board I'll be able to review with the requisite PC800 memory.

The features

The PC64 is expandable via its 5/0/1 design. Thus, 5 PCI slots, 0 ISA slots, and single AGP port. As well, the PC64 sports 2 184-pin SRIMM sockets, that can support upto 32 RDRAM chips, for a total of 1GB of memory.

As for configuring the PC64, what we are presented with is a truly jumperless board. Thus, there is no jumper to set; except for JP8 which is used to shunt audio signals to either an internal, or external speaker(s), as desired. In the BIOS, under the "CPU Frequency Control" menu, it is possible to adjust the clock multiplier, as well as the board's main bus frequency. Finally, within the "Advanced Chipset Features" menu, it is possible to select the RAMBUS module type in use, or allow it to be automatically determined by the system.

Note that this board provides no option for altering the processor's core voltage.

Available clock frequencies include: 66/75/83/100/105/114 and 120Mhz in addition to clock multipliers of 3X to 8X in steps of 0.5X.

Finally, an RT2 connector permits the user to plug in a thermal sensor, and measure an item of choice.

RAMBUS memory modules

RAMBUS memory modules come in an SRIMM configuration, and are composed of 4, 8, 12, 16 or more RDRAM chips. They are thus available in configurations of 64MB, 128MB, or 256MB. The maximum amount of memory that can be installed in a RAMBUS system in the real-world is limited by the single Rambus Channel that can only support upto 32 separate memory chips. For example, you could install two modules, each sporting 16 chips, on the PC64 - which has two SRIMM slots for memory expansion. If each chip can store 8MB, then 8MB * 32 = 256MB. One last peculiarity of the RAMBUS standard to be mentioned, is the requirement for the SRIMM with the greatest memory size to be installed in slot #1.

On the other hand, the RAMBUS architecture also requires that each SRIMM slot be in filled. So, in such a case as only a single memory module is installed, it becomes necessary to install a continuity circuit in the open slot, to assure that the electrical signal is routed properly. Fortunately for the user, such a circuit is typically supplied with the motherboard.

Next: Additional features.