so im putting new ram in my motherboard (which supports a maximum of 2133mhz) and because im a cheapskate im using ram that i had previously and a stick that was donated by a friend. 1 stick is 2133mhz Kingston and another is 2333mhz corsair vengeance lpx. And will having different speed and brand effect efficiency in my pc? i believe the 2333 will be automatically under clocked to 2133 i think.