Ok I've been posting in that Rage3D thread and it looks like those of us with non-identical monitors are going to struggle at the moment. Mine have just a slightly different size, which it seems is enough to cause the bezel compensation malarkly a problem...
HP LP2475w --- Screen size.............. 540 x 350 mm (25.3 in)
Samsung --- Screen size.............. 520 x 320 mm (24.0 in)
What's weird is that there's no way my hp monitor is 25.3 inches! My tape measure says 24.0 spot on (so does hp). I'm a bit new to this EDID stuff...is it possible for it to be wrong from the factory?
I have also had this problem, and started a new thread describing what I did to fix it. See here:
http://www.widescreengamingforum.com/forum/viewtopic.php?f=64&t=18597
I hope this helps you out.