No, that's not weird, as you don't get a proper reading from the NB concerning temperatures.
Newer versions of Everest for example do show *some* temperatures for MCP and SPP, but that's not a real temperature from what I can say so far. There's no sensor on the chip.

You may want to try to put a fan onto your graphics card to cool your NB heatsink, just to try if it does help you somewhere. Also, there was (?) a FSB hole around 400MHz FSB, so closely below and slightly above the board always needed much more voltage.
For example, I do need really high voltages around 360-380, but it's really stable with much lower voltages around 420. Maybe also worth a try.

What I got from another thread here -> it seems as all the temperature programs are quite off with the newer 45nm CPUs. I can't comment this as I haven't gotten mine yet, at least that's what I've seen on a couple of forums so far.