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KT600 motherboard round-up

Single-channel Socket A's last dance

DESPITE THE impressive performance and substantial potential of AMD's new 64-bit desktop processors, it's too early for me to get really excited about the Athlon 64 line. Don't get me wrong; the Athlon 64 3200+ and Athlon 64 FX-51 are great chips. However, their $400 and $734 respective street prices are bitter pills to swallow for anyone on a budget, especially considering the fact that Barton-core Athlon XP 2500+ processors are readily available for only $85 online.

Until AMD dramatically lowers its Athlon 64 prices or offers lower speed grades, the Socket A platform will remain quite popular among enthusiasts looking for the best bang for their buck. But what chipset will enthusiasts flock to for their Socket A needs? For some time, NVIDIA's nForce2 has been the Socket A chipset to have. However, the nForce2 is getting a little long in the tooth, and its lack of integrated Serial ATA support becomes more noticeable with each passing day.

The KT600, VIA's latest Socket A chipset, just happens to have integrated south bridge Serial ATA. But that's not all. The KT600 chipset officially supports a 400MHz front-side bus and features a tweaked memory controller that promises to wring every last drop of performance from its single memory channel. KT600 boards are making their way onto the market, and we've gathered eight of them for a massive mobo round-up. Just to keep things spicy, we've also thrown an nForce2 Ultra 400 board into the mix to see how VIA's latest Socket A creation stacks up against the well-entrenched competition.

Can VIA's KT600 run with or even beat NVIDIA's venerable nForce2? Which KT600 board is right for you? Read on as we compare boards from ABIT, ASUS, AZZA, EPoX, FIC, MSI, SOLTEK, and SOYO to find out.

VIA's KT600 north bridge

... and the VT8237 south bridge

The chipset
VIA's KT600 chipset isn't a radical departure from the KT400A, but VIA has managed a nip here and a tuck there to improve performance and to offer more features. The KT600 north bridge is primarily responsible for improved performance, while the chipset's VT8237 south bridge has all the new features. Before we cover all that's new and interesting in the KT600, let's see how it's all laid out in VIA's lovely block diagram:

Source: VIA

The KT600 block diagram nicely segments different elements of the KT600, which makes the chipset a lot easier for me to explain. Here are some of the highlights, starting from the top.

  • A 400MHz front-side bus - Despite its name, VIA's KT400A chipset never officially supported a 400MHz system bus. KT400 boards could often be overclocked, but not every board was stable at 400MHz. The KT600 officially supports 400MHz front-side bus speeds and provides all the necessary memory, AGP, and PCI dividers to keep the rest of the system running in-spec with AMD's fastest Athlon XPs.

  • Single-channel memory controller - VIA has tweaked the KT600's memory controller to squeeze as much performance as possible from a single channel of DDR400 memory. The KT600 won't be able to match the raw theoretical peak bandwidth of dual-channel DDR400 memory controllers, but it will have the distinct advantage of being competitive with only a single DIMM installed. Dual-channel solutions like the nForce2 require 2 DIMMs for optimal performance.

    Another often-overlooked benefit of single-channel memory controllers is how easy it is to expand a system's existing memory configuration¬óDIMMs can be added one at a time rather than in pairs.

  • Serial ATA - The VT8237 south bridge has native support for up to four Serial ATA devices, though accessing two of those devices requires an external PHY chip. Because it's located right on the south bridge, the VT8237's Serial ATA controller doesn't have to compete for limited PCI bus bandwidth with other devices. Serial ATA drives have full access to the KT600's 533MB/sec 8X V-Link interconnect.

  • V-RAID - VIA is serving up software RAID 0, 1, 0+1, and JBOD support for the KT600's VT8237's Serial ATA controller, which should delight mirroring and striping fanatics alike. Because V-RAID only works with south bridge-connected hard drives, it's not saddled with PCI bus bandwidth limitations that can plague third-party RAID chips. Using software built right into the driver, users can create and delete RAID arrays on the fly, designate spare disks, and even do array repairs.

    Unfortunately, V-RAID only works with Serial ATA drive connected to the VT8237 south bridge; "parallel" ATA RAID isn't supported. Because V-RAID only supports Serial ATA drives, RAID 0+1 support is limited to KT600 boards that expose the VT8237's extra two Serial ATA ports via an auxiliary PHY chip.

The KT600 chipset also inherits USB 2.0, six-channel Vinyl Audio, 10/100 Fast Ethernet, and 8X V-Link technology from the KT400A. Here's a quick synopsis of all the KT600's features:

CPU support Socket A-based AMD Athlon XP processors
Chipset VIA KT600
Interconnect 8X V-Link (533MB/sec)
AGP 4X/8X AGP 8X (1.5V only)
Memory Maximum of 4GB of DDR400/333/266 SDRAM
Storage I/O 2 channels ATA/133
Serial ATA 2 channels Serial ATA 150
RAID RAID 0, 1, and 0+1 for Serial ATA drives
USB 8 USB 2.0/1.1 ports
Audio Vinyl "Six-TRAC" 6-channel AC'97 audio
Ethernet 10/100 Fast Ethernet