Like you could run 16 bits programs with the 386, you can run 32 bits programs with the 64 bits (I have a 64 bits chip at home). For more details:

http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_9484,00.html
http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118_9485_9487%5E9505,00.html#91042

>I have a question......
>
>Will 64 bit PC systems ONLY run 64 bit programs, or will they be hybrids, that can run BOTH 64 and 32 bit programs....???
>
>Seems to me, that, only running 64 bit programs is like shooting yourself in the foot..... what about all the wonderful 32 bit apps out there? I think, in this case, MS might find out what it is like for an irresitable force to meet an immovable object.