Hi newcomer and welcome to the Tom's hardware forum.
1- Where do u read that?
2- U can OC with the 1333 RAM without problems the OC means find stable settings with the hardware that u have.
saint19 thanks but my question as I can with my OC Core i7 motherboard intel 930 DX58SO try to find the guide on youtube only find 920. I have problem with my BIOS setting thank you