rddave, maybe I'm missing someting, but I think you're being unrealistic about your fsb with either the qx6850 or qx9650. Certainly for a 24/7 stable setup.
The point of the QX's is that their multipliers are unlocked. You could try instead 10x400, 445 x 9 or 420 x 9.5 even.
If you want high FSBs then the dual cores or possibly the newer revision quads like the Q9650 are a better choice.
Just a thought
RLM