Motherboard upgrades and form factors?

I was trying to upgrade my computers CPU when i found out my motherboard didn't support the fsb speed i wanted. In my dell dimension 9200 the motherboard is a form factor BTX. Now i'm looking on intels website and all the potential upgrades are ATX or microATX. Does this mean none of them will fit? Cause i need 1333Mhz and all the BTX ones only go to 800Mhz. help please.