Some MBs have the option to run the RAM at their SPD rating automatically or by a manual change in BIOS. More than likely, in your case the RAM will default to 1066MHZ. No need for extra cooling either way. Your liquid cooling I presume is for your processor. It won't get any warmer. The FSB will stay the same. Just the memory multiplier will change if it runs at 1333MHZ.