Hi I have an older machine I may add ram to. - 1st gen I7 920 2.8 with corsair 1333 ram Asus P6TSE mobo Now I just realised my cpu only supports 1066 ram. But I have always had 1333mhz ram with no issues. Nothing is overclocked to my knowledge manually and cpu-z shows the RAM working at 1333 on my 1066 cpu. Having said this would the CPU still only communicate with the ram at 1066 speed ? cheers Lank.