Insane3D: I can agree with you regarding a somewhat dodgy ACPI header implementation on the SBLive.
Would you class the PCI latency patches as something that fixes a chipset issue?
The last several releases of the 4-in-1's were not to resolve any chipset issues as you claim.
Since you word it that way, at some point the VIA drivers do address issues which are chipset related. The point that I am getting at is that the issues resolved with the IAAs ONLY turn up with the IAAs installed. Case: Plextor burners had real problems burning with the ATA Storage Drivers (as they then were) when they were installed. If you never installed the drivers, there were no problems. From this, it can be concluded that the issue relates to the drivers and not the chipset.
With the VIA 4-in-1s, they are already included with Windows XP, which is why you do not have to install them. No such driver exists for WinXP as far as I understand. The same drivers are used for Intel IDE, regardless of it being a 400 series or 800 series chipset.