if it will make you feel better, DDR ram is backwards compatable, meaning even if your motherboard can only run PC2100 DDR ram, the PC3200 will run in it just fine. And yes, you will need to change the option in the bios for it to run at the 400mhz speed. That is if it can run the PC3200 ram
"What kind of idiot are you?"
"I don't know, what kinds are there?"