Overview of P4X400 and 648

Compared to its very successful 645DX brother, SiS’s new 648 chipset brings a great deal of new and improved features to the table. Among these features are:

1. AGP 3.0 (8X) support.
2. 1GB/s I/O interconnect, aka MuTIOL
3. Official Northwood-B (533MHz FSB) support
4. Native support for USB 2.0, 1394a (FireWire), ATA133, Ethernet, and basic 6-channel sound.
5. Unofficial support for DDR400 memory (SiS648 only “officially” supports as high as DDR333 memory).

For more detailed information on the SiS 648 chipset, please see our recent article entitled “Taking Advantage of the P4 Situation”.

In addition to "unofficial" DDR400 support, the P4X400 brings over all the same features from the P4X333 chipset we reviewed back in May. At the time of our P4X333 review, we were disappointed, to say the least, that VIA and Intel still hadn’t resolved their licensing conflict over the Pentium 4 bus. Our disappointment over all the legal turmoil stemmed from the fact that the features the P4X333 offered were the best out of any other DDR Pentium 4 chipsets we had seen at the time. The P4X333 brought features like native USB 2.0 and ATA133 support, DDR333 support (through an improved version of the KT333 memory controller), official 533MHz FSB support, an optimized PCI bus implementation, and a new V-link interconnect speed running at 533MB/s.

On another note, one can only wonder what would have happened had Intel and VIA settled their legal disputes before the P4X333 launched. In all likelihood, we would be seeing widespread adoption of the P4X333 (and now the P4X400) by top-tier motherboard makers such as Gigabyte, ASUS, and MSI among others. So while VIA enjoys top-tier mainboard support in the Athlon XP market, their situation in the Pentium 4 market is much more uncomfortable.

Index Looking at DDR400

Log in

Don't have an account? Sign up now