You can't, FirePro cards use CrossFirePro, which can't be used with CrossFire(X).
If you can manage to flash the BIOS of the FirePro to its Radeon equivalent or vice-versa then it could work.
You can't, FirePro cards use CrossFirePro, which can't be used with CrossFire(X).
If you can manage to flash the BIOS of the FirePro to its Radeon equivalent or vice-versa then it could work.