Tuesday, March 07, 2000

Introduction

It's been several weeks since I first received the AOpen AX6C motherboard for review, but due to a lack of RDRAM, it was impossible to review it. Frustrating, to say the least.

Finally, though, I was able obtain an RDRAM module, at a time when such things are selling for $950(USD). So then, it is with great pleasure that I bring you the review of the AX6C, and its very interesting characteristics.

First off, I want to mention that the AX6C is based on the Intel 820 chipset, also known as Camino. The AX6C thus supports RDRAM memory, 4X AGP, and ATA66 hard disk drives. If you remember, though, it is this same chipset that was long delayed due to a bug discovered by Intel late in the game. The bug itself manifested as a decided instability when working with more than 2 RIMM memory slots. Intel's solution to the problem was to tell motherboard makers to design i820 boards with only 2 memory slots. AOpen didn't follow that recommendation, due mainly to the fact that the AX6C design was already finalized by the time Intel discovered the bug, but also due to AOpen's decision that the board's stability was satisfactory. Did they decide wisely? Hopefully, this next gambit of tests will answer that question...

The features

The AX6C is expandable via its 5/0/1 design. That means you'll find 5 PCI slots, no ISA, and 1 AGP port onboard. In addition an AMR slot has been included in the motherboard's design. Finally, the 3 existing 184-pin SRIMM sockets can support a maximum of 1GB of memory.

As concerns configuring the AX6C, what we have before us is a totally jumperless design. This means that there are no jumpers to position, as the BIOS incorporates the functions necessary to adjust the parameters of the processor, and of the memory.

Within the BIOS, one finds the "Frequency/Voltage Control" menu, which permits the user to change the processor's clock multiplier (which has no effect with the PIII), the main bus frequency, and the memory's own clock multiplier. On that last point, I'd like to point out that the AX6C synchronizes the clock of the RAMBUS memory with that of the processor, and applies a selection of multipliers that includes: 2X, 2.66X, 3X, and 4X. By setting these various multipliers, it is possible to obtain 2X 100Mhz = 200MHz = (PC400 RDRAM 400Mb/sec), 3.0 x 100MHz = 300MHz ( PC600 RDRAM 600MB/sec), and 4.0 x 100MHz = 400MHz PC800 RDRAM 800Mb/sec). As well, RAMBUS memory, much like DDR-SDRAM, uses both the rising & falling edges of the clock cycle to transfer data, thus effectively doubling memory bandwidth.

Unfortunately, no option is provided for altering the processor's core voltage..

The AX6C's available bus frequencies, include: 100Mhz, 105Mhz, 114Mhz 120Mhz, 124Mhz, 128Mhz, 133Mhz, 138Mhz, 143Mhz, 148Mhz, 150Mhz, 152.5Mhz, 155Mhz, and 160MHz.

Comments

The first thing that I noticed about the AX6C is the horrendous positioning of the ATX connector, directly behind the processor.

Next, I was surprised by the size and numbers of the capacitors found near the processor, and the memory slots. With a configuration like this, the AX6C certainly won't be lacking for filtration.

Last, but not least, as the AX6C comes with 3 SRIMM slots, AOpen supplies 2 continuity cards to occupy open slots, because, as you may remember, the RAMBUS standard requires all slots to be physically occupied in order to complete the circuit.

Next: Features (continued).