The K8T900 & VT8251 Chipset Overview
When we scan the chipset schematic of the K8T900, the picture is very similar to that of the K8T890 when it was first announced. The K8T900 supports all AMD processors, including both single and dual core models from socket 754, 939 and 940. The K8T900 brings 20 PCI Express lanes to the table, represented as four PCI Express x1 slots and two PCI Express x16 graphics slots, with x8 electrical connections, linked directly to the Northbridge. We should note that VIA also spent some time tweaking the PCI Express implementation, claiming performance increases of 3-5% over the competition. We were told the same engineer that re-worked the KT266a's excellent memory controller tweaked the K8T900's PCI Express implementation.
Communication between the Northbridge and CPU is handled by VIA's Hyper8; a 16-bit HyperTransport Bus that runs at 1GHz (2GHz DDR) for 8GB/s of total bandwidth with socket 939 CPUs, while socket 754 and 940-pin configurations run at 800MHz (1600MHz DDR) for 6.4GB/s bandwidth. When combined with the VT8251 Southbridge, the K8T900 delivers a total of 22 PCI Express lanes, 20 with the Northbridge (x16 PEG and four PCI Express x1 connections) supporting 5 devices at 5GB/s of total bandwidth. The Southbridge offers two additional lanes totaling .5GB/s of bandwidth across two PCI Express x1 devices.
The VT8251 Southbridge brings eight USB 2.0 ports, seven PCI slots, 2-lane PCI Express and integrated 10/100 Ethernet. The Southbridge utilizes VIA's DriveStation to bring a host of storage features and flexibility. The DriveStation SATA controller offers 4 SATA II ports along with implementing Native Command Queuing for supporting devices. The controller also adds Hot-Swap capability along with staggered spin-up functionality to reduce power draw on initial startup. The parallel PATA controller offers two IDE connections supporting 4 ATA133 devices while VIA's V-RAID Controller delivers RAID 0, 1, 0+1, 5 and JBOD.
VIA offers three options in regards to integrated audio with VIA's Multichannel Audio Suite. The first is VIA's 20-bit/48kHz Vinyl AC'97 which is VIA's most basic 7.1 channel audio offering. The next level is VIA Vinyl HD Audio that brings 32-Bit 7.1 channel audio to the mix at 192kHz. Topping out the trio is VIA Vinyl Gold 7.1 surround driven by the VIA Envy24PT chip. Coupled with VIA Six-TRAC and an additional DAC, VIA Vinyl Gold offers the broadest array of features while delivering 24-bit /192kHz quality.