No Peter this is what I couldn't understand. Even my 4890 card which has a heatsink on the back still clears the northbridge.
Your board is different the P55 UD4/UD4P has about 7mm from the card edge (not from slot edge) so I can't see how the OP cards heatsink panel stick out more then 7mm.
Hi all,
As above, from card edge of the 16x slot to the Northbridge heatsink on the MB by my eye is 6mm.
From card edge of the VC 'to the Northbridge heatsink' is by my eye around 8 / 8.5mm.
The links to the VC images are correct and as can be seen there are four screws that secure the VC heatsink from the back - these screw heads are somewhat proud (yes secured fully) and it is this that fouls the fitting to the 16x slot. If the screws finished flush with the top of the plastic fitting plate it may well fit but this is not the case.
This 6mm distance strikes me as insanely close and must surely limit my VC options, to which your suggestions would be appreciated.