ddr2 800mhz ram with ddr 533mhz ram?

Man my question is i have a board that supports 533/667mhz ddr2 ram,can i insert a ddr 800mhz ram in this board,plz reply to my asap as i need to buy ram urgently.

^

yes..

but it ll work at 667.mhz..

Yes it will automatically underclock to lower frequency. But if you are able to buy the lower frequency used one (if available) it might save you some money as the 800 mhz one may be a little expensive. Just a hunch since I am not updated with hardware prices. Members, please correct me if I am wrong.