AGP 4x / 8X?

I have an ASUS CUSL2 mobo and an ASUS V9400-X video card and Win98SE (all updates).

The ASUS CUSL2 mobo has built in video and works fine but I cannot get the ASUS V9400-X video card to work on either the analog or digital out. The ASUS CUSL2 is 4X AGP and the ASUS V9400-X video card is 8X AGP, but it's supposed to be backwards compatible (maybe) see here:

http://wiki.answers.com/Q/Will_an_8x_AGP_video_card_work_in_a_4x_AGP_slot

I doubt the ASUS V9400-X video card is dead as I have never used it before and I bought it new some time ago, but never got around to installing it.

The ASUS V9400-X video card instructions call for the current VGA driver to be uninstalled before putting in the vide card, but from Device Manager it seems there is no VGA driver.

I used to get my answers on the CUSL2 here but the website is down
http://www.abxzone.com/forums/

Any ideas on how to get the ASUS V9400-X video card to work with the ASUS CUSL2 mobo. There is no BIOS or jumper changes to be made AFAICT.