The KT266 chipset

VIA's KT266 chipset consists of two chips: the VT8366 North Bridge and VT8233 South Bridge.

The chips!

Chipset basics 101

If you recall, traditional system chipsets contain two physical chips, the North Bridge (located on the upper portion of the motherboard and usually covered by a heatsink) and South Bridge (located near the bottom of half of the motherboard across from the PCI slots). The North Bridge of the chipset manages the flow of communication between the CPU, graphics card, and system memory. It's the North Bridge's job to act as a hub of communication between the components, ensuring information flows as efficiently as possible between them. The South Bridge handles components such as its integrated hard drive/USB/keyboard controller, and, in more recent times, onboard AC '97 audio is provided by the chip.

V-Link: Connecting the North to the South

Prior to VT8366, the PCI bus was used to connect the North Bridge to the South Bridge. Operating at 33MHz, the PCI bus offers a theoretical peak bandwidth of 133MB/sec. With the greater demands placed on the PCI bus by today's USB devices, PCI cards, and hard drives, the PCI bus can get bogged down more quickly than ever before.

To alleviate this potential bottleneck, KT266 utilizes VIA's V-Link bus to connect the North and South Bridge. V-Link is an 8-bit bus that operates at speeds of up to 133MHz, doubling peak bandwidth to 266MB/sec.

The memory controller

As we mentioned previously, the 8366 North Bridge supports DDR SDRAM (PC1600/PC2100) and SDR SDRAM (PC100/PC133). Like its predecessors, VT8366 also supports NEC's virtual channel SDRAM (VCM) and while VCM and SDR SDRAM can be used in mixed combinations, DDR SDRAM must operate alone. The VT8366 supports eight banks of SDR/DDR SDRAM up to 4GB, and like KT133, the DRAM controller supports both synchronous and asynchronous mode in relation to the front-side bus (FSB). This means the memory bus can run faster than the system bus to allow the use of 133MHz memory with 100MHz FSB, or it can run 33MHz slower than the bus to allow 100MHz memory to operate with a 133MHz FSB. This gives end users lots of flexibility when upgrading to a motherboard based on the KT266 chipset.

The South Bridge

The VT8233 South Bridge supports the latest technologies: two ATA/100 IDE controllers for support of up to four hard drives, support for six PCI slots (five bus masters), six USB ports (up from four supported by its predecessor), and six-channel AC-97 sound (previously only 2-channel). New features include integrated MC-97 modem and an integrated 10/100 fast Ethernet controller.

For the mobile market, VT8233 also supports AMD's PowerNow! Technology.

From a features standpoint, KT266 is clearly superior to AMD-760, as it offers a more feature-rich, flexible design. However, ALi's MAGiK 1 DDR chipset offers most of the same features, with the biggest exception being maximum memory size, MAGiK 1 only supports up to 3GB of memory.