I see you don't have a clue about SIS's Xabre and NV18. Both of these products are 8X AGP capable.
These were cross posts without a refresh, but I'm sure you knew this.
That is not the issue since those cited motherboards worked with other 8X AGP capable cards.
Ok, let's take a look and see who is at fault, ATI or the reviewers of these cards (note the Xaber update in the Gigabyte bios). These are the bios versions that were available at the time you claim these cards were reviewed.
[color=CC0000]MSI 648 MAX
BIOS Type AMI® BIOS File Size 491KB
Version 1.1 Update date 2002-9-27
Update Description -Fixed system unstable when using ATI 9700
-Fixed error message sometimes appear after S3 resume
-Fixed S3 resume failed when USB legacy set as enabled
Special note ,
Download 6585v11.exe [/color]
** Soltek I could only locate the SL-85ERV2 on their site, and they list no bios updates that I could see.
[color=CC0000]Asus P4S8X BIOS 1003A
1003A 2002/08/27
Serial ATA ROM updated 376.bin(016).
Patch ATI AGP 8X.
Support Intel Pentium 4 2.8Ghz CPU.
[/color]
[color=0000CC]Gigabyte GA-7vAXP last 3 bios updates
7vaxp_f7.zip F7
(Oct. 25, 2002) 1. Disable CPU fast command when FSB166Mhz CPU plugged.
2. Modify top performance setting frequency.
3. Fixed SIS Xabre AGP card STR fail on win98\ME.
7vaxp_f6.zip F6
(Oct. 07, 2002) 1. Fixed system hang under win98 when Creative PCI sound card exist
2. Improve CPU to AGP performance for ATI AGP card.
7vaxp_f5.zip F5
(Sep. 05, 2002) 1. Mass production release.
[/color]
[color=CC0000] Via P4PB400
Version (Date) 1.13 (01/03/2003)
File Name (Size) P4PB4113.bin (257KB)
Update Description Support high capacity HDD
Version (Date) v1.10 (10/16/2002)
File Name (Size) P4PB4110.bin (257KB)
Update Description add LAN Boot and Enhance other functions
Version (Date) 1.05 (08/29/2002 (08/29/2002)
File Name (Size) P4PB4105.bin (257KB)
Update Description Enhance Some bootable device
Version (Date) 1.00 (07/22/2002)
File Name (Size) P4PB4100.bin (257KB)
Update Description First Release [/color]
So 3 of the 5 boards you listed already had bios updates several months before this site tried to review the card. Soltek doesn't list ANY type of bios updates, and Via is extremely vague about what the fixed in the update. Anyone with half a clue about PC products knows to check for bios updates and chipset updates when an entirely new product like this hits before they try to use it.