Thanks for the answer.
On the Gigabyte website you linked to, it said that not all CPUs would support the DDR2 1066.
"Whether 1066 MHz or above memory speed is supported depends on the CPU being used."
If I have the AMD Athlon II 620 (http://www.newegg.com/Product/Product.aspx?Item=N82E16819103706&cm_re=AMD_athlon_II_620-_-19-103-706-_-Product),
will this CPU allow me to use 1066?