I've never heard of a "too fast" issue with RAM, unless what you got is for a 667MHz FSB, and your PC has a 400 MHz FSB. In this case the "multiplier" is AFU. My suggestion is return the RAM and get RAM appropriate for your PC, making sure the speed of the FSB is the same as your RAM.
If you can't return it, eBay...or Craigs List...
Kurt.