I just bought an AsRock DUAL VSTA board as a transitional mobo, so that I can continue to use my IDE drives and AGP videocard, while upgrading to a CD2 processor. The AsRock has 2 DDR2 slots (and 2 DDR slots), rated at PC667. Although I still have DDR 400 from my old setup, I only have 1 GB total, and want to get 2. With their prices being so close, I would rather buy an 800 kit than a 667 kit, so that when I later move to new mobo, I won't have to upgrade my RAM again. Will DDR2 800 RAM work in a DDR2 667 system? Thanks for your help!!