That's also something I'm a bit confused about, because it says "Its driver software (which is required to enable acceleration) is compatible with System 6 (driver version 1.0) and System 7.0-7.1 (driver version 7.0.1), but will not run under System 7.5 unless the Mac is in 24-bit addressing mode" (they also mention the PPC card+ATI drivers possibility). So does that mean the card won't work at all in 7.6 without 24-bit mode, or is this only for enabling acceleration in 7.5?

This is a upgrade card for the Quadras, not sure if it's PPC tho. No, I'm not planning on doing it that way I think..