What you have to change is the ratio it runs at you cannot unlink the memory speed from your FSB. On the P5Q change the FSB strap to like 266 or 333 and then change the Dram frequency to whatever is closest to 1066.
i have the same prob i have kingston khx8500d2t
which should be 1066MHz but only clocks up to 800MHz
They run at 800MHz because you didn't manually set the frequency and voltage. Since they require 2.2V to run at 1066MHz, I wouldn't bother. I would instead use the fastest settings requiring 2.0V or less. Use CPU-Z to view the SPD table contents and post it here if you have questions.