I'm also a novice at overclocking, but the northbridge is more officially known as MCH (Memory Controller Hub) and I have also seen that this sometimes needs a boost.
(Edit: just read sutahz's post and agree as well. Below are just some general tips I have read.)
If you're trying to get an optimal overclock I've read you really need to change things in a methodical manner. There are procedures you can follow that will take a lot of the guesswork out of the game. For instance, if you just start increasing you Vcore and FSB, then when you hit a wall, you don't know if this is caused by: 1)FSB wall of MB, 2)FSB wall of CPU, 3)Max freq of CPU, 4)Max DDR freq, etc... A methodical approach will separate each of these primary limiting factors and allow you to determine which is holding you back in the final overclock and thus, what should be changed next to overcome the block.
There is an excellent
walkthrough stickied at the top of this page. Make sure you've read that before continuing. It doesn't seem to have a lot of the stuff I've read about testing your RAM and FSB first, so that must be floating around here somewhere (maybe someone can find it and post a link).
IIRC, the idea was to test the MB/CPU FSB limit by using a low multiplier (6x) on your chip along with loose memory timings and a low memory speed (controlled by the strap); set CPU Vcore, MCH, and Vram to max comfortable settings and then start cranking up the FSB to find its max. Then you probably want to back off a bit and test for stability. Once you know that, you can test for memory speed by increasing the strap. Once you have an idea of the frequencylimit of the memory (with loose timings), set the strap back to 1:1 (synchronous) and start increasing the CPU multiplier to see how high you can go. You already know you're at a stable FSB and memory so any limit you hit should be due to max CPU freq. Multipliers jump the frequency in big steps, so once you hit a wall, you may want to try reducing the FSB to the equivalent of one multiplier lower and slowly raising it to find the limit. Once you get the CPU where you want it, then you tighten down the memory settings and finally, you start reducing voltages a little bit at a time to find the lowest stable voltages.
It should be noted that I have never done this, only read about it and regurgitating from my memory so I will graciously defer to any experienced users opinions. But I think as long as you stick with safe voltages and temps, you should be OK. Good luck.
