I've recently bought an ASUS P4C800 mb and an HIS ICEQ9800pro 128mb GC. I cannot enable either fast write or AGP X4/X8 from the GC's software. The m/b user guide states that it supports AGP X8 at 0.8v or X4 at 1.5v. I think my GC is 3.3v (according to 3d mark '05)so is this the reason I cannot enable AGP X8 or fast write?. The system is stable but can anybody answer to what extent it is being slowed down by not being able to use the two features?