Hey. I RMA my Gigabyte, got a Asus P8H67-M LX which was about half as loud then finnaly bought a expensive MSI P67A-C65 with the advert of "whistle free", well guess what, this one does it too. Disabling C state only way to fix. Tested all with 3 differant PSU and power sockets as well as fanless cpu/gpu and PSU wired to another room.
However Gigabyte board was by far the worst in loudness, Asus was bad enough to hear and MSI with all my fans on with case closed under my desk I can just about make it out(I think, hard to determin source).
I bought a USB PCI controller when I found unplugging all USB seemed to dim it, but it doesn't seem to on MSI board, I'm going to have to put up with it and bin it when a new model comes out.
Good luck with your replacement, i'm pretty conviced all 1155 boards do though and no one accually sits them on a test bed, they just stick them in their case and end up thinking the noise is from their PSU etc.
