nForce2 Dethroned? VIA's KT400A Chipset Reviewed

The Competitors: NVIDIA, SiS

We don't want to go through all the Athlon chipsets again, as there is a comprehensive article available: Then and Now: Athlon Platforms Compared .

Dual Channel Vs. Single Channel

Of course, there is one heavy reason why dual-channel memory configurations are extremely favorable: they offer twice the bandwidth of a single-channel setup. As a result, performance can be much higher than with conventional systems. All Rambus chipsets except the very first (i820 alias Camino for the Pentium III) are based on a dual-channel architecture; SiS is currently working on a quad-channel Rambus version of their 658 chipset for the Pentium 4. NVIDIA was the first to introduce a two-channel memory controller to the Athlon platform; VIA is going to follow this summer.

There are, however, several cons that might speak against dual-channel systems. The first and possibly most practice-related is the fact that you need two identical memory modules. And that's not all: if possible, you should even use identical DIMMs in order to avoid trouble. This has been a reason for systems based on the SiS655 chipset being handicapped: if the two modules aren't identical, the system might run considerably slower.

Let's also think about the cost factor: two memory modules are usually more expensive than a single DIMM. In addition, the memory controller is more complex and thus requires more transistors and more silicon, driving costs up again. That's exactly the niche that VIA tries to address: nForce2-like performance at the cost of a conventional chipset.

Chipset Diagram

The updated chipset diagram already shows the new southbridge including the Serial ATA controller. We will focus on this new piece of silicon in a separate article soon.