Ok i have a motherboard that supports both ddr1, and ddr2, which you can easily tell by the slots, i ordered 2 sticks of ddr2 to accompany my ddr1, thinkin it would just clock down to the speeds of my ddr1 ram, however whenever i put them in together, it wont boot up, which leads me to the question on whether or not you can do this.. thanks for you guys' help