XPanding Chipset Choices: The Latest Athlon XP Chipsets

XPanding Chipset Choices: The Latest Athlon XP Chipsets

The Athlon XP processors are amazingly speedy processors, not so much in terms of clock speed (the so-called Athlon XP 2800+ has an actual clock speed of just 2.25GHz), but in how quickly they perform typical tasks at a given clock speed. In achieving great performance at relatively modest clock speeds, Athlon XP processors are greatly aided by the latest chipsets and their support for faster DDR memory, faster interconnects between North and South Bridge chips, and other innovations. In this article, well take a closer look at the highest-performance chipsets for Athlon XP processors.

VIA Offers Two DDR333 Solutions: KT333 and KT400

VIA Technologies has long led the list of Athlon supporters and the features found in its latest chipsets, the KT333 and KT400 help keep it on the short list of top chipset choices.

The KT333 and KT400 both support DDR333 (PC2700) DDR SDRAM memory, enabling 333MHz FSB speeds, but beyond that, they differ greatly in their features, thanks in large part to the South Bridge chips used by each chipset and the speed of the V-Link connection between North Bridge and South Bridge chips.

KT333 - Your Choice of South Bridge Chips Changes What You Get

The KT333 can be viewed as the "mainstream" or "economy" DDR333 chipset, depending upon which South Bridge chip is used with its VT8367 North Bridge chip, a 552-pin ball grid array (BGA) chip. The VT8367 North Bridge provides the following features:

• Support for 200MHz through 333MHz FSB, enabling the chipset to be used with older Socket A Athlon and Duron processors as well as the latest Athlon XP processors
• Up to 4GB of onboard RAM
• AGP 2x/4x video slot
• Support for VIAs standard 266MHz (4 x 66MHz) V-Link connection to the South Bridge.

However, depending upon the South Bridge chip chosen by the motherboard maker, your low-speed device options can vary a good bit. The KT333s North Bridge can be used with any of the South Bridge chips shown in Table 1.

Table 1-VIA South Bridge Chips

The easiest way to determine if a KT333 motherboard is using an 8233-series chipset or an 8235 chipset is to look at the USB level supported. 8233-series chipsets support USB 1.1, while the 8235 chipset also used by the KT400 supports USB 2.0. However, some vendors which use the VT8233A South Bridge with the KT333 use a separate USB 2.0 chip to add USB 2.0 support. Motherboards which use an add-on USB 2.0 controller chip will list both USB 1.1 and USB 2.0 ports. Note that only the 8233C supports a 3Com 10/100 network controller (the others use a software LAN feature with a riser card), and only the 8233A and 8235 support UltraATA-133, the fastest Ultra ATA hard disk interface currently available.

If the KT333 is sufficient to your needs, you should look for motherboards that use the VT8235 South Bridge chip if you want the most up-to-date USB and hard disk support.

KT400 - DDR333 Performance with the Latest I/O Technology

Because it can use South Bridge chips left over from the previous generation of 266MHz DDR memory motherboards, you could consider the KT333 a transitional design with its mix of old and new features. If you want the very latest which VIA Technologies has to offer, look for motherboards that use the KT400 chipset.

While the KT400 supports the same 333MHz (PC2700) DDR SDRAM as the KT333, it can also support some of the emerging 400MHz (PC3200) DDR memory now on the market. Note that many motherboards actually run slower when 400MHz DDR memory is used because 400MHz memory isnt an established standard as yet (check with the motherboard vendor for suggested memory modules). Also, note that early tests KT400-based boards by Toms Hardware Guide and AnandTech showed little difference in performance between 333MHz and 400MHz DDR modules, and, for that matter, between KT333 and KT400-based motherboards.

If youre mostly concerned about current processors and performance, motherboards based on the KT333 chipset might be sufficient. However, as processor and memory speeds rise, and official standards for 400MHz DDR memory eventually arrive, the features built into the KT400 should manifest themselves in faster system performance. The KT400s 664-pin VT8369 North Bridge supports AGP 4x/8x, so that youre ready for the fastest video performance as it is released. The KT400 doubles the speed of its V-Link South Bridge connection to 533MB/second (V-Link 8x), enabling faster data transfer between UltraATA drives and other devices and memory. Because the KT400 uses the VT8235 South Bridge, you can use fast UltraATA-133 and USB 2.0 drives for even greater speed.

The Latest from SiS

SiS (Silicon Integrated Systems) is best known for its low-cost integrated chipset solutions for Intel and AMD processors, but SiS has also joined the DDR333 bandwagon with its SiS746 North Bridge chip. The 746 can be paired with the SiS961, 962, or 963 Media I/O (South Bridge-equivalent) chips.

The SiS746, which comes in a 713-ball BGA package, supports AGP 2x, 4x, and 8x, and up to 2GB of 333MHz DDR memory. As AMD did with its chipsets, SiS has developed a fast connection between the North Bridge and South Bridge chips, the 533MHz (133MHz x 4) MuTIOL connector technology providing up to 1.2GB/second bandwidth depending upon the Media I/O chip used with it. MuTIOL is divided into three layers to carry bus master, North Bridge-Media I/O, and memory to Media I/O traffic at high speeds. Unfortunately, while the 746 supports 333MHz DDR SDRAM, it doesnt support AMDs 333MHz FSB processors (Athlon XP 2700+, 2800+ and faster). An improved version may do so.

Depending upon which Media I/O chip used with the SiS746, the motherboard will support various features, as shown in Table 2.

Table 2-SiS MuTIOL Media I/O Chips

For best performance and the broadest range of features in an SiS746-based motherboard, look for a motherboard which uses the SiS963 Media I/O chip.

nVidia nForce2 - A Powerful Sequel

While nVidia is most famous for its popular GeForce line of 3D graphics chipsets, its becoming a significant player in the motherboard chipset business as well. We first wrote about the original nForce chipsets with our July 2001 article NVIDIA's nForce Invades the Motherboard Chipset Market. As new processors and memory types have been introduced in the meantime, nVidia has reworked nForce to create its new line of chipsets, nForce2.

nForce2, like the original nForce, uses a dual-channel memory design for faster memory bandwidth., supporting DDR memory with speeds up to 400MHz and up to 266MHz FSB. Because the memory is accessed in a dual-channel mode, nForce2 is able to reach memory bandwidth speeds of 5.4GB/second with standard DDR 333MHz memory, a speed much faster than you can reach with dual PC800 RDRAM modules (3.2GB/second) such as those used by the much more expensive Intel 850-series chipset.

The nForce2 family features a completely modular design, enabling motherboard designers to mix and match features based on the choice of North Bridge-equivalent and South Bridge-equivalent chips. If you want built-in graphics, choose an nForce2 motherboard with the Integrated Graphics Processor (IGP) as the North Bridge. If you want to add your own graphics card from the start, save money by choosing a motherboard with the System Platform Processor (SPP) as the North Bridge. Both support AGP 8x video, so you can add a separate video card to an IGP-equipped system if you need better 3D performance at a later date.

Just as you can choose between "bring your own graphics" or integrated video with the nForce2s North Bridge family, you can choose between two different South Bridge-equivalent chips, the MCP (Media Communications Processor) and MCP-T (which adds additional features). Both feature UltraATA-133 support and 6 USB 2.0/1.1 ports, but the standard MCP supports only a single network port and 6-channel business-quality sound with SPDIF out. Pick a motherboard with the MCP-T chip instead, and you add IEEE-1394a ports, a second network port from 3Com (very handy for using Internet Connection Sharing on a broadband network or for bridging two networks), and nVidias APU (audio processing unit) with advanced 3D sound and Dolby Digital 5.1 encoding.

Because of the mix-and-match nature of the nForce2 family, nVidia markets three different nForce2 solutions, the Digital Media Platform, Gaming Platform, and the Business Platform. Essentially, the Digital Media Platform and Gaming Platform use the IGP and MCP-T combination, while the Business Platform is based on the SPP and MCP combination. Table 3 shows how these combinations compare in features.

Table 3-nForce2 Entertainment versus Business Platforms

nVidia has licensed AMDs HyperTransport high-speed connection to tie the IGP/SPP North Bridge to the MCP/MCP-T South Bridge. HyperTransport offers a bandwidth of 800MB/second, putting it in between the older and newer versions of SiSs MuTIOL in performance. HyperTransport also exceeds the speed of VIAs V-Link.

For Further Research

To learn more about these chipsets, see the following sources.

VIA KT333 and KT400:

VIA Technologies official KT333 website is located at
http://www.via.com.tw/en/apollo/KT333.jsp

VIA Technologies official KT400 website is located at
http://www.via.com.tw/en/apollo/kt400.jsp

Visit VIA Arena, VIA Technologies official support portal at
http://www.viaarena.com

SiS746:

The SiS746 website is located at
http://www.sis.com/products/chipsets/oa/socketa/746.htm

nVidia nForce2:

The nForce family website is located at
http://www.nvidia.com/view.asp?PAGE=nforce

Product Tests:

nForce2 motherboard tests from Toms Hardware Guide
http://www6.tomshardware.com/mainboard/20021111/index.html

nForce2 motherboard tests from AnandTech
http://www.anandtech.com/mb/showdoc.html?i=1759

KT400 motherboard tests from Toms Hardware Guide
http://www6.tomshardware.com/mainboard/20021007/index.html

Anandtechs tests of the KT400 include Gigabyte 7VAXP
http://www.anandtech.com/showdoc.html?i=1721

Soyo KT400 DRAGON
http://www.anandtech.com/showdoc.html?i=1714

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