Originally Posted by Kama
One question though ... so I assume I have a 5900NU board now, but does that require a different type of heatsink/fan combination than the 5900XT boards?
The only answer I can give is, if the memory chip layout is the same as a 5900XT then you get a XT heatsink, otherwise your card's memory chip layout should be same as for 5900nu, 5900u, 5950u and thus you get a heatsink for this type. You should be able to check the different memory chip layouts of XT and NU cards on any FX manufacturers website.
And for improved cooling; If we take the Arctic FX Coolers for example, the correct heatsink assembly for a FX5900XT would be,
And for a 5900nu type would be,
But of course for extreme gpu cooling, WATER is a much better way to go !!