I have just added a 6 pin connector to the power supply in the xw6400.
The PSU is decent enough but very lacking in connectors. By default it only had one 6 pin connector and only two molex
one of which is powering the DVD drive.
So the second 6 pin required to power the GTX 460 was fed 12v from only one molex. Not ideal.
Just had the PSU open, it wasn't the easiest to play with, got some wires from an old PSU and solderd them to the underside of the board (as that was the only place I could get access to).
It's all back up and running and I feel that bit safer