ive installed this ram: corsair ddr3 4gb 1333mhz (x2),
but when i open speccy, it states that the mhz is 666mhz,,,is there some type of setting i need to do?
Another way of saying it: DDR stands for "Double Data Rate," which means that it transfers data twice per clock cycle, as opposed to once per clock cycle for older SDRAM.
So as stated above, the effective speed is twice the real speed, and perfectly normal.