VIA Chipsets slow down PCI cards

Limitations of the VIA patch, Version 1.01

But in contrast to George Breeses universal solution VIAs patch only helps a limited number of people: It only works with Ultra-ATA-cards by Promise. Even when patched, the performance of a VIA chipset with ATA/133 cards by HighPoint or ACARD is unchanged and poor.

Burst transfers with Ultra-ATA/133-controller

Chipset	ACARD AEC-6280	Highpoint RocketRAID 133	Promise Ultra133 TX2
All scores taken with Maxtors DiamondMax D740X
VIA KT266A without Patch	87,7 MByte/s	83,3 MByte/s	83,5 MByte/s
VIA KT266A with Patch	87,7 MByte/s	83,7 MByte/s	104,2 MByte/s
VIA P4X266A without Patch	89,6 MByte/s	81,2 MByte/s	90,1 MByte/s
VIA P4X266A with Patch	89,7 MByte/s	81,2 MByte/s	111,3 MByte/s

In addition, there is another limitation of the patch VIA won't tell about: It only increases performance with chipsets that feature VIAs V-Link technology. VIA uses V-Link since the release of the Apollo Pro266. The highspeed chip-to-chip bus V-Link can sustain transfer rates of up to 254 MByte/s and interfaces between the North- and the Southbridge. Older chipsets like the KT133A or MVP3 do not offer higher burst transfer rates with VIAs patch. These chipsets connect the Southbridge to the Northbridge as a PCI device.

Therefore VIAs patch does not solve the problem of the weak PCI performance of all of VIAs chipsets. At least, one can completely remove the patch through Windows' control panel.

We checked back with VIA, and they promised to come up with a better solution. The patch version 1.01 vanished from their sites, however, the links to the file itself are still working. On Friday, February 01, 2002, VIA finally came up with version 1.04, described on the next page.