possibly a bad board, more likely a bios setting regarding the ram is a little off on your board. check ram latency/voltage as well as nb voltage. if the values are nominally correct, give them a little boost just to see what happens. you wont damage anything as long as you dont go crazy with it
The complete memory management/controller could be having problems. Try setting timings/voltages manually and setting proc. to stock (no OC at this point) and see what happens. A lot of times it throws errors at wrong timings and some boards won't always run RAM at optimal without manual configuration. Try that and see what happens. If that doesn't work, may need to try different RAM in the boards; it could just be a compatibility issue between the RAM and mobo. If you need assistance setting timings, ask. There should be answers for it on here though, or at least Google it and a video is *probably* around for similar Gigabyte boards.