I really cant OC my i5 2500k.When i go into the BIOS the multiplier is locked on 37 ( 3,7 GHz ) Why? Yes i have an K edition . My mobo is Gigabyte PH67A-UD3-B3 . I have an old bios version ( F2 ) and there is F5 i think . I tried to update my bios but it says it needs a 32bit operation system or something .