Northbridge temp

That might be normal given your OC. I'd keep an eye on it, especially under load -- you may have to add cooling for it. Remember that just like the CPU, the NB's power use/heat goes up with the FSB. Since all memory I/O is going through the NB, memory use will also stress the NB.
 
how do you know the NB temp outside the bios? might sound a bit noobish but i never seen any NB temp on speedfan/core temp/real temp...