afaik, the motherboard automatically chooses loose timings .. so all sticks might run at CL6
but there is another possibility too .. since OCZs are 1066 Mhz CL6 , they might run at 800 Mhz CL5
i have KHX6400D2LLK2\4G CL4 as well .. these will run at CL5 when paired with CL5 RAM sticks.