[H]ard|OCP has a VERY active thread about the problems people are encountering with the 680i chipset.  They also have a news post that talks about what is known for sure, and what is likely the cause.  Unfortunately, right now it seems to be luck of the draw when it comes to problem free motherboards.
“Out of the gate, the nForce 680i chipset from NVIDIA seemed to be the best Core 2 Duo overclocker going, that is of course when your system is not plagued with BSODs and data errors. You need to read this if you are considering a 680i motherboard.”

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