It is no secret that NVIDIA nForce2 is the fastest solution for Socket A platform in almost all cases. This success can be explained by a very successful memory controller implemented in this chipset. It is not just a dual-channel controller. It also supports very interesting DASP algorithm, which allows the chipset to save some data, which the CPU might need later, from the system RAM into the buffer in advance. That is why when the CPU really does request this particular data, it will be able to get them not from the slow RAM but from a much faster internal buffer, which will reduce the latencies this way.
However, one of the major advantages of this chipset, its dual-channel design, is at the same time one of its major drawbacks. This is quite true, as this feature reduces the memory configuration flexibility, because the memory modules used in the system should better be the same, i.e. you have to replace them in pairs, which can hardly be considered convenient. Moreover, the use of two memory channels sets much stricter requirements to the PCB layout and its components, which definitely affects the production cost a lot. Since the mainboard manufacturers are no altruists, the higher production expenses influence the final product price for the end-users, of course. And keeping in mind that computers have already become one of the common home appliances, every user will surely pay close attention to the end-system cost. So, nForce2 will no longer look that attractive, from this point of view. Besides, some business users working on AMD platforms are hardly very eager to pay extra money for an office PC, especially if they never actually use their maximum performance.
For some of the reasons mentioned above, single-channel chipsets are still the most attractive solution for many Socket A system users. NVIDIA also realized this and launched a single-channel version of its nForce2 solution aka nForce2 400, which supports 200MHz bus of Athlon XP processors and the newest PC3200 memory. However, NVIDIA is not the only chipset maker to support this memory type. VIA and SiS also introduced their solutions of the kind: VIA KT400A and SiS746FX. So today we are going to talk about these two babies, mostly about the VIA KT400A, of course :)