clkspd=5

i have a system whose configuration is following-: Intel pentium D 3.0 GHz, Intel original motherboard 946, Transcend RAM DDR2 667 Mhz 512MB clkspd=5, Kingston Ram DDR2 667 Mhz 1 GB clkspd=5. I want upgrade my memory, so i want to purchase a 2 GB DDR2 RAM Stick 667MHz clkspd=5. But now it...