VIA K8T900 AMD Chipset Preview
Finally! The 8251 South Bridge
We have looked at the VIA 8251 south bridge more than a few times in the past. To say we have had our hopes raised only to be let down would be letting VIA off too easy. This time, VIA seems to have things ready. The VT8251 south bridge chip is in full mass production with some new features and is expected to appear on all of the design wins that the K8T900 is on.
VIA still has the same feature set that we saw listed for the 8251 over a year ago including two lanes of PCI Express, SATA and RAID support, 8 USB 2.0 ports, integrated 10/100 Ethernet support, VIA Vinyl audio and Ultra V-Link support for connection to the VIA north bridge chips.
Probably the most interesting addition to these features is support for SATA II and 3.0 Gb/s hard drive speeds. The south bridge has support for command queuing as well as AHCI support, so you no longer need to load a driver with the F6 command during Windows installation. The new SATA controller has four separate channels so that each drive gets an independent path to the south bridge. Port multipliers are also supported here, though they are less than popular in the market.
VIA took the time to add on to their RAID functionality this time around by adding RAID 5 to the already known list of RAID 0, 1 0+1 and JBOD on the VT8251. RAID 5 is probably one of the more interesting developments in storage recently as it allows you to have the fault tolerance of RAID 1 coupled with the increased performance of RAID 0 with only three drives and still have the capacity of two of them. NVIDIA's nForce4 MCPs support this feature as well.
The VT8251's audio support includes support for Azalia, standard AC'97 audio and even the VIA Vinyl on-board 7.1 channel surround sound chip, the Envy24PT that can run 24/96 resolution to digital outputs. This is one advantage that the VIA south bridge has over the nForce4 MCPs at this point.