Yeah, I know my xw8400 is a bit past her prime - but she's still solid as a rock and working great with MC 6.03.2. I'm using a MXO2 mini and, to my surprise, it's working great with my setup. My question is - which slot did any xw8400 owners use for the MXO2 mini? I'm using slot 4, but I keep reading to use slot 3 - any thoughts? salud