Hello.
This card is a card game, it does not seem the most appropriate for Multibrige.
The only slot for multibrige that you can use is the number 3, in single card mode (slot 1: vga (x16 mode), slot 3: multibrige (x4 mode)).
If this no works, then other bios settings are: “boot graphic adapter priority” and “High priority port select”. Try with this settings.
Luck