Tom's Hardware > All Reviews > Components > Motherboards > Mega Test: 14 Boards with KT266A and nForce 420D

VIA Changes Their Naming Convention

06:00 - Monday 26 November 2001 by Frank Völkel

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

Chipset	VIA Apollo KT266A	VIA Apollo KT266	Nvidia nForce
Introduction	September 2001	April 2001	September 2001
Platform	Socket 462	Socket 462	Socket 462
Supported processors	AMD Duron/Athlon/XP	AMD Duron/Athlon/XP	AMD Duron/Athlon/XP
Multi-processor support	no	no	no
Northbridge	VIA KT266A	VIA VT8366	Nvidia IGP 128
Southbridge	VIA VT8233	VIA VT8233	Nvidia MCP-D
Front Side Bus clock	100/133 MHz DDR	100/133 MHz DDR	100/133 MHz DDR
Memory clock	100/133 MHz DDR	100/133 MHz DDR	100/133 MHz DDR
Asynchronous memory clock	yes	yes	yes
FSB overclocking*	up to 200MHz	up to 200MHz	up to 150MHz
Max. # DIMM slots	4	4	3
Max. memory	3072 MB	3072 MB	4096 MB
SDRAM support	yes	yes	no
DDR SDRAM support	yes	yes	yes
Dual-channel DDR support	no	no	yes
RIMM support (Rambus)	no	no	no
Ultra-DMA/33/66/100	yes/yes/yes	yes/yes/yes	yes/yes/yes
# USB connectors	6	6	6
Max. # PCI slots	6	6	6
integrated graphics core	no	no	yes
integrated sound	yes	yes	yes
AGP 1x / 2x / 4x	yes/yes/yes	yes/yes/yes	yes/yes/yes
ACPI supported	yes	yes	yes

* depends on clock generator

UltraATA/133

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.