Friday, January 05, 2001

Introduction

The DFI AK74-AC is the first motherboard we've received that is designed to work in conjunction with the new line of Athlon DDR266 processors from AMD. This new line of CPUs - as you may guess - operate with a DDR front-side bus clocked at 133MHz. In order to accommodate this newer, faster bus, the AK74-AC is designed to use the recently released KT133A chipset from VIA, and includes the new VT2C686B Southbridge. That said, the AK74-AC isn't capable of taking full advantage of the new AMD CPUs, as it does not support DDR266 memory. In fact, the AK74-AC seems essentially to be a revised version of the AK-74SC. With that being said though, lets head on to the analysis, and see just what may set this board apart from its peers.

Features

Traditionally speaking, DFI's motherboard products haven't tended to feature any BIOS functions that are likely to raise any eyebrows, and the AK74-AC is no different. First off, there are no BIOS functions allowing the CPU's VIO voltage to be adjusted. Second, there is are no options allowing the clock multiplier to be set manually. Worse yet, there are no options allowing IRQs to be manually assigned, which is often the only way to get things running smoothly when an IRQ conflict occurs.

On the other hand - as you can tell from the table above - DFI has been very generous in the FSB department, and the available frequencies are separated into two groups, or levels. The first group spans the gap between 90MHz, and 130MHz and is available when jumper JP10 is closed. The second group of higher frequencies ranging from 133MHz to 166MHz becomes available when JP10 is left open.

Adjustment of the memory bus frequency is possible from within the "Chipset Features Setup" menu - as is the case with most boards these days - and allows it to function at either 100MHz or 133MHz. As far as memory latencies are concerned though, only CAS latency is adjustable by the user; most boards offer the ability to adjust other settings such as RAS to CAS latency.

As far as graphics are concerned, it's also worth noting that features such as Fast Write, AGP 1 WS Master Write, and AGP 1 WS Master Read are missing.

For those interested in the KT133A chipset itself, it's worth mentioning that the VT86362A Northbridge is capable of adequately supporting frequencies greater than 133MHz, as well as the AMD DDR266 bus. The VIA VT2C686B Southbridge, for its part, supports ATA100 drives - a notable step up from the 686A, which supports only the slightly older ATA66 standard.

Technical details

A limited amount of space is available around the CPU socket, which makes it difficult or impossible to install larger heatsinks.

The memory slots are far enough from the AGP port that there is no chance of the retention clips coming into contact with the graphics card.

Twelve 1500Mfd capacitors have been placed around the CPU socket.

The CPU retention lever is made of plastic, so handle with care.

The AK74-AC includes 3 fan connectors.

Hardware monitoring is controlled by the chipset.

Manual assignment of IRQs is not possible with this board.

There is no heatsink or fan installed on the Northbridge as seen on many similar boards using this chipset.

No function has been included that would allow the BIOS to be rolled-back to the last set of valid settings. Thus, if the system refuses to boot, the BIOS must be manually reset.

Next: Additional features.