Closer Look: VIA KT400A Chipset

As you may have already guessed from the chipset name, it is a successor of KT400 solution, which was at first supposed to support PC3200. However, shortly after the chipset launch, there appeared some problems with the implementation of this support: the chipset performance when working with PC3200 turned out much lower than in case of PC2700. Moreover, KT400 chipset didn’t know to clock the memory at 200MHz when the system bus frequency equaled 166MHz. These pretty strange phenomena could be explained by the absence of a general JEDEC standard for PC3200 (they couldn’t even call it PC3200, but only DDR400). A little later, mostly due to Intel’s initiatives, PC3200 DDR SDRAM turned into a standard and the manufacturers got the opportunity to announce support of this memory type without being afraid of any compatibility issues.

It is interesting that VIA with its KT400A followed NVIDIA in a way, which had implemented the data prefetch DASP algorithm even in the first nForce chipset. VIA called its technology FastStream64, which was probably supposed to imply the 64bit memory bus of the KT400A chipset unlike 128bit memory bus of the nForce2, which could also ensure high level of performance. However, this doesn’t change the idea of the technology behind the name. FastStream64 is a much bigger number of internal chipset buffers compared with what the other VIA’s products can boast.

Judging by the description on the company site, VIA was at first going to supply KT400A with the new VT8237 South Bridge supporting SerialATA. However, their plans changed and we can see the new VT8237 only with the KT600 chipset, the next solution from VIA for Socket A platform (read our article called Contemporary Socket A Chipsets: NVIDIA nForce2 Ultra 400, NVIDIA nForce2 400, SiS748 and VIA KT600 for details). Besides that, KT600 will also support AMD Athlon XP processors with 200MHz bus and will boast “enhanced” PC3200 DDR SDRAM support. All in all, this will be just another chipset remake, which VIA has always been famous for. We should say that VIA is still a little behind SiS in terms of support for Athlon XP processors with 200MHz bus. SiS has already officially launched SiS748 chipset supporting these processors, while VIA is only getting close to KT600 release. Although we wouldn’t call this a dramatic lag. The thing is that SiS has always been slow in bringing the freshly announced solutions to the mass market, and even though the company is now using UMC’s production capacities, the actual selling schedule for SiS748 based mainboards is still unclear. Besides, the CPUs with 200MHz bus are not very widely spread yet.

All in all, KT400A (even the way it is now) is quite functional, and its pin-to-pin compatibility with the previous chipsets from VIA should make it much easier for the mainboard manufacturers to shift to production of new boards on this core logic set. Anyway, the puzzling names of the new chipset do not make the mainboard manufacturers and the users any happier that is why KT400A is not that popular yet. Many mainboard makers decided simply to ignore the VIA KT400A, believing that it doesn’t differ that much form the KT400. Nevertheless, we got a few mainboards on VIA KT400A in our lab and we are going to tell you a little more about them. The first one we would like to introduce to you today is MSI KT4A Ultra.