The latter is a 650i costing 70 pounds sterling and a great overclocker.
The former costs 90 pounds sterling (I think) and is a slightly better overclocker than the Fatal1ty board.
The latter has a red PCB but the NB gets very hot after a massive overclock (~80 degrees C).
The former has a yellow PCB and no cooling issues that I can think of at this time.
Those are my two recommendations if you want a great overclock.
Korrd knows everything there is too know for quick overclocking I think. And i support increaseing the voltage instead of buying a new motherboard.
You do have a custom cooler right and not the reference heatsink...
It seems that Asus P5B Deluxe is also a good one. I think we could replace the current one with this one. It's the same chipset and maybe it would run with the current system instalation. I'd like to avoid installing it from scratch again...