Can i run a hdmi through the motherbord but still use a radeon 4670

Welcome to the forums!

You can try. It may work.
The 4670 connection would be better.
Here is an adapter for $3.63:

http://www.monoprice.com/products/product.asp?c_id=104&...

You can use the connection on the MB, but it would have to use the 3600. This would be fin if it is for a secondary display, such as a tv you watch movies on, but would be pointless if it is for the primary display you use for games etc as it would defeat the purpose of owning the 4670.