You can't keep the ram exactly at 1066 unless you set your cpu frequency exactly right. The 1066 is the fastest rated speed for the ram, but it can run slower. Actually it might run faster or it might not.
What you need to do is to set the ram multiplier in your motherboard to get as close to 1066 as you can without passing it. With a Q9300 at 3.57, your mobo should be at 476mhz, and you should set your ram multiplier at 1:1 (or 2.0 depending on the motherboard's terminology), and your ram will run at 952.