CAS3 DDR2-1344 is nearly impossible or unbelievable if you'd ask me and others. [ at least with current DDR2 ICs ]
And 3.1V wouldn't be enough even if the modules were capable of reaching that frequency at CAS 3.

The only way to prove this and make sure that it's not the bug, is to use a P35 or X38 motherboard, and have it validated with CPUz again.