VIA Flex Express Architecture

Of the many exciting technologies to debut in 2004, perhaps the most significant is PCI Express, which consolidates and replaces the existing PCI and AGP buses. As the PC increasingly deals with demanding entertainment and multimedia applications, such as high definition video, multistreaming audio and the latest 3D games, ever increasing demands are being placed on system bandwidth. To meet these changing requirements the industry is transitioning to PCI Express connectivity, which delivers the bandwidth needed for today’s most bandwidth hungry applications, as well providing the headroom needed for future generations of applications.

A technology shift as significant as the shift from PCI and AGP to PCI Express inevitably throws up multiple challenges for the PC Industry and end-users, as new bus architectures, interfaces and connectors create numerous compatibility headaches. VIA's unique Flex Express Architecture has been designed with the specific intention of easing the transition to PCI Express, allowing the industry’s most flexible implementation of VIA core-logic chipsets supporting the PCI Express standard, and minimizing compatibility issues.

Flexible PCI Express Configurations

The VIA Flex Express architecture allows multiple device configurations, supporting connections of up to seven PCI Express devices across a maximum 22 PCI Express lanes with a maximum theoretical bandwidth of 5.5GB/s.

¹ Including connection to PCI Express Graphics

VIA DualGFX Express™

A solution that stands ready to support all dual graphics card industry standards, VIA DualGFX Express provides enhanced single application performance with supporting graphics cards and multi-monitor support for power multitasking without tying up vital system bandwidth. Taking advantage of the reduced cost of multiple LCD display panels and easier multi-display set up with today’s operating systems, VIA DualGFX Express makes multiple monitor displays of up to four panels viable for an increasing base of users.

Diagram 1: Dual GFX Express and PCI Express peripheral device configurations of sample VIA North Bridge paired with VT8251South Bridge

Distributed PCI Express Bandwidth

By supporting PCI Express x1 peripheral connections through both the North and South bridges of the chipset, the VIA Flex Express architecture distributes PCI Express bandwidth across the whole system architecture, thus minimizing potential bottlenecks. Enabling PCI Express connections to peripheral devices directly through the North Bridge frees up South Bridge bandwidth, which is increasingly being taken up by multiple connections to IDE and SATA drives, as well as numerous USB2.0 and 1394 peripheral devices.

Diagram 2: Available PCI Express device configurations of sample VIA North Bridge paired with VT8251.

Expanding PCI Express to Mature Platforms

The flexible nature of the Flex Express architecture also brings PCI Express connectivity to mature VIA chipset-based platforms. The pin-compatible design approach for VIA’s core logic chipset solutions potentially allows the VT8251 South Bridge to be paired with mature VIA North Bridges, such as the PT880 and PT800 for the Intel processor platform, and the KT880 and K8T800 Pro for the AMD Athlon XP and Athlon 64 processor platforms. In combination with the VT8251 South Bridge, these platforms can support two PCI Express x1 peripheral devices with 250MB/s of bandwidth per direction, per device.

Unparalleled Design Flexibility

The pin-compatible design approach of the VIA’s acclaimed V-MAP (Modular Architecture Platform) enables flexible VIA North and South Bridge configurations, allowing industry partners to cover multiple market segments with a single board design. Through this approach, OEMs and motherboard vendors can minimize development costs and speed up time to market by consolidating their product lines on a standard but scalable platform that enables them to meet the diverse needs of multiple market segments through the rapid integration of different feature sets.

Ultra V-Link Bus

A key component of V-MAP is the Ultra V-Link bus, a 16-bit 66MHz client interface that delivers data throughput speeds of up to 1066 MB/sec between the chipset's North and South Bridges. The Ultra V-Link bus delivers the necessary bandwidth and low latency required by today's increasingly bandwidth hungry I/O devices, as well as constantly increasing CPU and memory bus speeds. Not only does the Ultra V-Link speed up data transfer rates, it also addresses potential bottlenecks on the South Bridge that may be created by the increased bandwidth of new PCI Express peripheral devices requiring 250MB/s bandwidth, and other high-speed connections such as USB2.0 and 1394.

Hyperion 4in1 Drivers

VIA’s unified Hyperion driver base optimizes system performance while maintaining full stability and compatibility, and facilitates any technical support required. A pioneering unified driver set, the VIA Hyperion 4in1 drivers are compatible with all systems running Microsoft Windows® operating systems.