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Mega Test: 14 Boards with KT266A and nForce 420D

VIA Changes Their Naming Convention

Good bye old cryptic VT... something. The old KT266 northbridge is still known under VT8366 whereas the new baby KT266A is also called KT266A.

Four CPU types for socket A are available. All of them are now supported by KT266A and nForce 420D.

Comparing The Chipsets - VIA Vs. Nvidia

ChipsetVIA Apollo KT266AVIA Apollo KT266Nvidia nForce
IntroductionSeptember 2001April 2001September 2001
PlatformSocket 462Socket 462Socket 462
Supported processorsAMD Duron/Athlon/XPAMD Duron/Athlon/XPAMD Duron/Athlon/XP
Multi-processor supportnonono
NorthbridgeVIA KT266AVIA VT8366Nvidia IGP 128
SouthbridgeVIA VT8233VIA VT8233Nvidia MCP-D
Front Side Bus clock100/133 MHz DDR100/133 MHz DDR100/133 MHz DDR
Memory clock100/133 MHz DDR100/133 MHz DDR100/133 MHz DDR
Asynchronous memory clockyesyesyes
FSB overclocking*up to 200 MHzup to 200 MHzup to 150 MHz
Max. # DIMM slots443
Max. memory3072 MB3072 MB4096 MB
SDRAM supportyesyesno
DDR SDRAM supportyesyesyes
Dual-channel DDR supportnonoyes
RIMM support (Rambus)nonono
# USB connectors666
Max. # PCI slots666
integrated graphics corenonoyes
integrated soundyesyesyes
AGP 1x / 2x / 4xyes/yes/yesyes/yes/yesyes/yes/yes
ACPI supportedyesyesyes

* depends on clock generator


Some manufacturers are gradually updating their KT266A based products, as there is one controller with ATA/133 support already available: HighPoint's HPT372. It is pretty much the same chip than the HPT370 ATA/100 RAID controller, supporting RAID modes 0, 1, 0+1 and JBOD (spanning). Of course you can also attach any other ATA drive without any RAIDing. Just be careful with CD-ROM drives, DVD ROMs or writers: All of them use the ATAPI interface which is not supported by most IDE RAID controller chips.

More About The nForce - 128 Bit Memory Bus

One of the main characteristics setting the nForce chipset apart from the VIA KT266A is its dual-channel DDR SDRAM interface. This means that two 64 bit DIMM modules are merged to create a 128 bit wide memory bus.

But there are a few snags: The Nvidia chipset will only reach peak performance with two identical RAM modules. If, however, a third RAM module is added to the fray, the dual-channel mode, with its 128 bits of bandwidth, is automatically deactivated. That fact alone makes upgrading RAM tricky at best, pumping up the price as well.

What's more, there's no way to determine which mode the board is running. Asus is planning to address the problem by integrating a special display feature in future BIOS versions.

The graphics integrated into the board are derived from the GeForce2 MX, which addresses memory according to the shared-memory system. All told, up to 64 MB RAM can be reserved for graphics functions.