SLI or Crossfire a problem?
Many of the 3rd party chipset coolers will be larger then the default one, the NC-U 6 is not different, although it has a quite slim design, its height will make it difficult to fit a longer VGA card if your chipset is right behind the PCI Express slot.
On the Asus A8N-SLI Premium the chipset sits between the two 8x PCI Express slots, which surely comes in handy:
A close fit, the 7900GT used it not as long as the 7900GTX or newer 8800GTX, so some problems may still arise; if you use mid-range VGA cards, the chipset cooling can fit correctly;
Throwing a 7800GT in the mix makes it a tighter fit:
It’s still do-able, although longer VGA with dual slot
cooling will not fit with the NC-U 6 installed.
Some performance tests and conclusion next ->