The guys at the Inq have checked out the northbridge temps on several of the top-end enthusiast motherboards, & it looks like the nForce 680i is a scorcher. The problem is that with certain manufacturer-implemented cooling systems, you're pretty much stuck as-is, unless you trust the mosfets to keep themselves cool enough on their own...

"And, even with the massive multi-level heat pipe labyrinth on the current benchmark reference, Asus Striker Extreme, augmented by three fans, there was still immense finger-scorching heat emanating from the chipset portion - after all, even Nvidia monitor showed at least 55 C in most cases."